Concrete Tech Guide

Bouygues bâtiment International – Engineering division – BES BA Practical Guide : The concrete on the international market

PRACTICAL GUIDELINESCONCRETE ON INTERNATIONAL

MARKET

Author: Camille d’ArnouxSupervisor : Marc Blondeau2007


Pathway to determine a suitable concrete for a construction

In order to create a durable construction, you must:-use a durable material

-design the structure according to environmental factors-carry out proper checks on the quality of the materials and on construction techniques

Normative / contractual

restraints

Materials and concrete

ProcessPlacing /

Special concretes

Specificcharacteristics ofthe construction

Pathology/ Risk Prevention

Surroundingsand exposure ofthe construction

Normative constraints

AggregatesDaily

requirements

Special concretes

HeightGeographical

zone

Contractual constraints

CementCapacity of

the mixing plant

Standard method forplacing concrete

Length ofspans

Immediatesurroundings

Particular methods of placing

Admixture SurroundingsDistance between

jointsGround / Water

table

Mixing waterSite mixing plant

/ Ready mixLarge units Particular

conditions for use

ConcreteAttractive

appearanceLife period

Architecturaldesign

Checks


PART A: SPECIFIC CHARACTERISTICS OF THE WORKS1 – Height…………………………………………………………2 – Length of spans…………………………………………….3 – Distance between joints …………………………………4 – Large units ………………………………….………………5 – Attractive appearance …………………………………….

PART B: ENVIRONMENT AND EXPOSURE OF THE CONSTRUCTION

1 – Geographical zone ………………………………………......2 – Immediate surroundings ……………………….…………..3 – Ground / water table…………………………………………4 – Particular conditions of use………..……………………..5 – Building life time…………………………………………….Appendix – Corrosive effect of chemicals……………..

PART C: CONCRETE PATHOLOGY / RISK PREVENTION DATA SHEETS

1 – Cracking / Shrinkage …………..……...……………….....2 – Maritime environment …………………………………......3 – Alkali reaction……………………………………………....4 – Freeze / Thaw …………………………………..………......5 – Sulphate attack………………………..……………………6 – Acid attack …………………………………………………..7 – Corrosion of the reinforcement …….…………………...8 – Carbonation…………………………………………………9 – Chloride attack………………….……………………….....10 – Surface appearance …………………………………......Appendix – Summary of the essential criteria for a durable

concrete ………………………………………………………..

A2A3A4A5A6

B2B3B4B5B6B7

C2C4C5C10C12C13C14C15C16C17

C20

PART D: NORMATIVE AND CONTRACTUAL CONSTRAINTS1 – Normative constraints

1-1 – Europe………………………………………………………1-2 – USA…………………………………………………………1-3 – Russia………………………………………………………1-4 – Other countries ………………………………………..

2 – Contractual constraints …………………………………PART E: MATERIALS AND CONCRETES

1 – Aggregates1-1 – Mineralogical nature ……………………………………..1-2 – High sulphate, sulphide, chloride content…………1-3 – Shape of the grains ……………………………….1-4 – Granularity………………………………………………….1-5 – Cleanliness of the aggregates ………………………1-6 – Water and porosity ………………………………..Appendix 1: Selection criteria according to use of concrete

………..Appendix 2: Main normative references…………………

2 – Cement2-1 – Manufacture of a cement …………………………...2-2 – Hydration reaction of the cement………………………2-3 – Europe – EN 197-1

2-3-1 – Description of a typical cement……………………2-3-2 – Additions………………………………………………2-3-3 – French specifications .....……………………………2-3-4 – British specifications .....……………………………2-3-5 – Main European normative texts .…………….

2-4 – USA 2-4-1 – ASTM C150: Specification for Portland cement….

D2D3D4D4D4

E3E4E5E6E7E8E9E10

E13E14

E15E16E17E19E20

E21

CONTENTS


2-4-2 – ASTM C595: Specification for blended cement….. 2-4-3 – ASTM C1157: Standard performance for hydraulic

cement ……………………………………………………..2-4-4 – Summary table…………………………………2-4-5 – SCMs: Supplementary Cementitious

Materials……2-5 – Important note: Europe / USA………………………….2-6 – Russia: Main normative texts relating to cement..

3 – Admixtures3-1 – Consistence of the concrete

3-1-1 – Plasticisers / Water reducers……………………….3-1-2 – Superplasticisers ………………………………3-1-3 – Properties, mix proportions, application ………

3-2 – Setting / Hardening3-2-1 – Setting / hardening accelerators……………..3-2-2 – Setting retarders ………………………………3-2-3 – Properties, mix proportions, application ………

3-3 – Properties of the concrete 3-3-1 – Air entrainer …………………………………3-3-2 – Waterproofing compound…………………………3-3-3 – Properties, mix proportions, application ……

3-4 – Choice of admixture type depending on its properties 3-5 – Standards: Main normative texts relating to admixtures ..4 – Mixing water …………………………………………….5 – Concrete

5-1 – EN 206-1: Concrete – Part 1: Specification, performance, production and conformity

5-1-1 – Introduction ……………………………

E22

E22E22E23

E24E25

E27E27E28

E29E29E30

E31E31E32E33E33E34

E36

5-1-2 – Classification5-1-2-1 – Exposure …………………………………………5-1-2-2 – Consistence of fresh concrete ……………5-1-2-3 – Compressive strength of hardened concrete ..5-1-2-4 – Chloride content………………………………5-1-2-5 – Maximum size of aggregates…………..5-1-2-6 – Density………………………………..

5-1-3 – Definition of concretes for placing an order5-1-3-1 – BPS: Designed Concretes………….5-1-3-2 – BCP: Prescribed Concretes …………5-1-3-3 – BCPN: Standardised Prescribed Concretes .

5-1-4 – Recommendations for concrete composition limits5-1-5 – French specifications .....……………………………5-1-6 – British specifications .....……………………………

5-2 – Specification of fresh concrete in the USA ………5-3 – Russia: Main normative texts relating to concrete..

6 – Checks on concrete: Main normative texts……Appendix: Main worldwide suppliers of materials.

PART F: PROCESS1 – Determination of daily requirements…………………..2 – Determination of the capacity of the mixing plant ……..3 – The construction’s immediate surroundings …………..4 – Site mixing plant / Ready Mix concrete delivery:

Selection criteria …..Appendix: Diagram of ready mix concrete plant ……………

E37E40E40E41E41E41

E42E42E42E43E44E45E48E49E50E54

F2F3F4F5F6

CONTENTS


PART G: PLACING AND SPECIAL CONCRETES1 – General placing of concrete1-1 – Formwork ………………………………………….1-2 – Transport……………………………………………………1-3 – Vibration of the concrete ……………………………1-4 – Curing of the concrete ……………………………1-5 – Formwork removal ……………………………………. 1-6 – Daywork joints …………………………………….

2 – Special concretes2-1 – Compact and low permeability concrete ……2-2 – BHP: High-performance concretes…………………..2-3 – BAP: Self-placing concretes ………………………..2-4 – Fibre concretes ……………………………………….2-5 – Architectonic Concrete …………………………………2-6 – Lightweight and dense concretes …………………..2-7 – Pumped concretes ……………………………………. 2-8 – Other special concretes………………………………..

3 – Architectural design…………………………………. 4 – Particular methods of placing concrete

4-1 – Complex shapes and high densities of reinforcement ..4-2 – Concreting of large units………………………….4-3 – Concreting in hot weather………………………….4-4 – Concreting in cold weather………………………….

APPENDIX: Guidelines for concrete mix designGLOSSARYBIBLIOGRAPHY

G2G4G5G8G10G11

G12G13G15G18G19G22G23G24G25

G26G27G28G29

CONTENTS


Page A 1

Constraint to be checked Risk Solution Link

Key used on the following slides

Part A: SPECIFIC CHARACTERISTICS OF THE CONSTRUCTIONS

1 – HEIGHT ………………………………………………………………………Page A 2

2 – LENGTH OF SPANS…………………………………..………….………..Page A 3

3 – LIMITATION OF JOINTS……………………………………………………Page A 4

4 – LARGE UNITS………………………………….…………………………..…Page A 5

5 – ATTRACTIVE APPEARANCE ………………………………………….…Page A 6


Page A 2

All the elements at the same floor level are not loaded in the same way. There may be differential settlement in the various elements in the same construction when the differences in stresses are large.In the case of a High Rise Building, the phenomenon may be observed between the columns on the external walls and the central core, consisting of walls.The settlement will vary over time and depending on the load applied.Generally, the phenomenon must be considered and included in the design if the tower is taller than about 150 m.

CONCRETE WITH IMPROVED

MECHANICALCHARACTERISTICS

or High-performance concrete

HEIGHT

Differential settlement betweenstructural elements

Examine the deformations due to creep and shrinkage

Increase the strength of the concrete

Concerns high rise buildings:

-Residential towers-Office towers

- etc.

High forces in the vertical elements

Modify / adapt the structureto take the forces

Modify / adapt the structureto distribute the forces

1 – HEIGHT

CRACKING /SHRINKAGE

DESIGN BY CONSULTANT

Page G 13

Page C 2

For indicative purposes, for a standard concrete, the levels of stresses in a vertical element is close to 10 MPa in a column and 5 MPa in a wall.


Page A 3

For indicative purposes, under the effect of traditional loads, there may be a need to use:For the spans of slabs:- Up to 8 m: traditional concrete- From 7 to 9/10 m: plank floors, pre-stressing- Greater than 9/10 m: honeycomb slabs or post-stressingFor the spans of beams:- Up to 15 m: traditional concrete- Over 15 m: post-stressing / pre-stressing

LENGTH OF SPANS

Non-compliance with permissible deformations

of horizontal elements in bending

High forces in the vertical elements

Choose a suitable concrete and / or suitable construction

processes

Concerns constructions likely

to have great spans:- Stadia

-Shopping centres-Multi-sports complex

-Etc..

Increase the strength of the concrete

Modify / adapt the structureto take the forces

2 – LENGTHS OF SPANS

CONCRETE WITH IMPROVED

MECHANICALCHARACTERISTICS

or High-performance concrete

CRACKING /SHRINKAGE

DESIGN BY CONSULTANT

PRE- / POST-STRESSEDELEMENTS

Page G 13

Page C 2


Page A 4

DISTANCE BETWEEN JOINTS

For indicative purposes, the recommended distances between expansion joints:- In France: vary between 25 and 50 m depending on the region - In Singapore: may be up to 80 m

CURING

FIBRE CONCRETE

Shrinkage capable of causing structural

problems(cracking)

Careful supervision of concreting

Thermal gradient capable of causingstructural problems

(cracking)

Include suitable reinforcement

Increase the number of joints if possible

Choose a suitable concrete

Must take into account:

-local recommendations /

standards-the architecture

-the moisture content-Etc.

Definition:Expansion joint: Joint allowing movement due to thermal deformation caused by differences in temperature. Shrinkage joint: Joint designed to concentrate shrinkage cracks in large-scale concrete constructions.

The final objective is to have control over the size of the cracks and to distribute them.

3– DISTANCE BETWEEN JOINTS

CRACKING /SHRINKAGE

DESIGNBY CONSULTANT

Page G 18

Page C 2

Page G 8

HIGH-QUALITY CONCRETE

Page G 12


Page A 5

LARGE UNITS

CURING


Careful supervision of installation

LARGE CONCRETE CONSTRUCTIONS

FORMWORK

Concerns units thicker than 0.8 m:- Raft foundations

- Large load-bearing units-etc.

In general, cracking will occur when the difference in temperature Is greater than 20°C either between 2 concrete sections or between the concrete element and the external air

Surface or throughout cracking resulting

from the concrete’s exothermic reaction

CRACKING /SHRINKAGE

4 – LARGE UNITS

METHOD OF PHASING / PLACING

Page G 27

Page C 2

Page G 2

Page G 8


Page A 6

PATHOLOGY /PREVENTION ON FACINGS

ATTRACTIVE APPEARANCE

Defect in appearance, colour, texture

Comply with the construction specifications

Careful supervisionof installation


Concerns constructions and buildings for which the architects want

to highlight its attractive surface

appearance:-Numerous public

buildings (hospitals, schools,

administrative buildings, etc.)

-Etc.

5 – ATTRACTIVE APPEARANCE

Page C 17

ARCHITECTONIC CONCRETE

Page G 19


Page B 1

Part B: SURROUNDINGS AND EXPOSURE OF THE CONSTRUCTION

1 – GEOGRAPHICAL ZONE …………………………………………. Page B 2

2 – IMMEDIATE SURROUNDINGS…………………………………………....Page B 3

3 – GROUND / WATER TABLE…………………………………….…..Page B 4

4 – PARTICULAR CONDITIONS OF USE ……………………….…..Page B 5

5 – BUILDING LIFE TIME……………………………………………….Page B 6

APPENDIX – CORROSIVE EFFECT OF CHEMICALS………….…..Page B 7

Above all, when arriving in a new country, take a close look at nearby constructions, particularly constructions that are damaged, under repair or repaired and look for the reasons.

Take a close look, also, at the general appearance of nearby constructions, including the appearance of the concrete, the existence of exposed reinforcement and efflorescence (whitish stains) on vertical surfaces.


Page B 2

SEISMIC REGION

VIBRATION OF THE CONCRETE

Heavily-loaded structural elements

WEATHER CONDITIONS

TEMPERATURE

CONCRETING IN COLD WEATHER

CONCRETING IN HOT WEATHER


Choose a suitable concreteReduction in the durability of the

various constructionSundry pathologies

HUMIDITY

WIND


Choose a suitable concreteCONCRETE

WITH A HIGH DENSITY OF REINFORCEMENT

Climate Types of pathologies

Cold temperate climate

Freeze/thaw cycles and high humidity levels:- Internal cracking due to freeze/thaw(Page C 10)- Spalling due to de-icing salt (Page C 10)- Corrosion of the reinforcement (Page C 14)- Amplification of the phenomenon of alkali reactions in the aggregates (Page C 5)

Temperate hot and humid climate

- Attack by corrosive water - Amplification of the phenomenon of alkali reactions in the aggregates (Page C 5)

Dry climate - Carbonation (Page C 15)

In order to evaluate the risks, consult the local weather stations to obtain long-term statistics of weather conditions (prevailing

wind, frost, etc.).

PATHOLOGY /PREVENTION

FREEZE / THAW

1 – GEOGRAPHICAL ZONE

Page C 10

Page G 29

Page G 26

Page G 5

Page G 28


Page B 3

MARITIME SITE

EXPOSURE TO AMBIENT AIR

CORROSIVE WATER

FREEZE / THAWDE-ICING

SALTS

PATHOLOGY /PREVENTION

FREEZE / THAW

PATHOLOGY / PREVENTION

MARITIME SITE

PATHOLOGY / PREVENTION CARBONATION

Follow the prevention principles

Reduced construction

durability

The most exposed constructions are those subjected to moderate

humidity and to air.

2 – IMMEDIATE SURROUNDINGS

TABLE OF CORROSIVE AGENTS

Page C 15

Page B 7

Page C 4

Page C 10


Page B 4

WATER TABLE

GROUND

SULPHATESPRESENT AND

CONCENTRATION

"NON-TRADITIONAL"ELEMENTS IN THE

GROUND

SALTS CONTENT AND CONCENTRATION

pH OF THE WATER

Examples:- Gypsum - Anhydrite-Etc.

Examples:-Heavy metals-Hydrocarbons-Erc.

FRESH WATER

- Magnesium- Sulphates- Ammonium

Identify the risk(s) and follow the prevention

principles


durability

3 – GROUND / WATER TABLE


Page B 7


Page B 5

RISK OF CONDENSATION OR DAMPNESS

PRESENCE OF CORROSIVEPRODUCTS

PRODUCTION OF GAS

Examples:- Production of steam- Laundry room- Swimming pool areas- Etc.

Industrial building- Acids - Chlorine- Chemicals-Etc.

Examples:-Carbon dioxide-Etc.

Identify the risk(s) and follow the prevention

principles


durability

4 – PARTICULAR CONDITIONS OF USE


Page B 7


Page B 6

PERIOD OF USE

The durability of a construction is characterised by its capacity to retain, under the conditions anticipated, the functions of the use for which it was designed (structural functions, security and

safety, comfort in use) and to maintain its level of reliability and its appearance, within its environment, with planned and reactive maintenance costs that are as low as possible.

Designing a durable construction requires an understanding, right from the design stage, of all environmental constraints and potential attacks to which it will be subjected by its intended use, for

the whole period of its service.

Whatever precautions are taken to adapt and to optimise the formulation of the concrete, it will only be able to fulfil its function durably if "good trade practice" has been followed during its installation

(correct vibration, suitable curing, allowance for weather conditions when concreting, shrinkage fully under control, provision of correct cover to reinforcement, etc.). In order to obtain the specified durability, it is

necessary to follow the recommendations and the standards for the execution of the works.

Changes in the performance level of the concretes can also be evaluated by durability indicators, such as its permeability to oxygen, the diffusion of chlorides and the speed and the depth of carbonation.

Standard EN 206-1 includes requirements on the basis of an assumed lifespan of at least 50 years.

5 – BUILDING LIFE TIME


Page B 7

Corrosiveness of acids on concreteInorganic acids Organic acids

Name and formula corrosive effect Name corrosiv

e effectH2SO4

Sulphuric acid Formic acid

H2SO3Sulphurous acid Acetic acid

HClHydrochloric acid Tannic acid

HNO3Nitric acid Humic acid

H8PO4Phosphoric acid Lactic acid

H2SHydrogen sulphide Oxalic acid

H2CO3Carbonic acid Fermentation liquids

HFHydrogen fluoride

Corrosiveness of salts to concrete

Name and formula corrosive effect Name and formula corrosiv

e effect

Sulphates

NaSO4-KSO4Sodium/potassium

sulphate

Chlorides

FeCl2Ferric chloride

(NH4)3SO4Ammonium sulphate

AlClAluminium chloride

MgSO4Magnesium sulphate N

itrates

NaNO3, KNO3Sodium/potassium

nitrate CaSO4

Calcium sulphateCa(NO3)2

Calcium nitrate

Al2(SO4)3Aluminium sulphate

NH4NO3Ammonium nitrate

Fe(SO4)3Ferrous sulphate

CaHPO4Superphosphate

Chlorides

NaCl KClSodium/potassium

chlorideSulphides

NH4ClAmmonium chloride Fluorides

CaCl2Calcium chloride Silicates

MgCl2Magnesium chloride Carbonates

High corrosiveness

Fairly high corrosiveness

Medium corrosiveness

Low corrosiveness

Non-corrosive

Organic acids arise generally from waste water from sugar refineries, paper mills, tanneries, dairies, tinning factories, distilleries, etc.On urban sites, sulphate corrosion is extremely frequent.

PATHOLOGY / PREVENTION

ACIDS

PATHOLOGY / PREVENTION SULPHATES

PATHOLOGY /PREVENTION CHLORIDES

The following table sets out the level of corrosiveness of various acids, sulphates, chlorides, nitrates, etc.

ANNEXE – CORROSIVE EFFECT OF CHEMICALS

Page C 13

Page C 12

Page C 16


Page C 1

Part C: CONCRETE PATHOLOGY / RISK PREVENTION DATA SHEETS

1 – CRACKING / SHRINKAGE …………………………………………………………….…......Page C 2

2 – MARITIME ENVIRONMENT..............................................................................................Page C 4

3 – ALKALI REACTION…………………………………………………………………..….………Page C 5

4 – FREEZE / THAW…………………………………………………………………..….………....Page C 10

5 – SULPHATE ATTACK ………………………………………………………………………..….Page C 12

6 – ACID ATTACK ……………………………………………………………………………….…..Page C 13

7 – CORROSION OF THE REINFORCEMENT ……………………………………….…….…..Page C14

8 – CARBONATION……………………………………………………………………………….…Page C 15

9 – CHLORIDE ATTACK ………………………………………………………………………..…..Page C 16

10 – SURFACE APPEARANCE……………………………………………………………….…….Page C 17

APPENDIX – SUMMARY OF THE ESSENTIAL CRITERIA FOR A DURABLE CONCRETE ....Page C 20


Page C 2

Sedimentation / BleedingDropping of the heaviest components under gravity.→ segregation, settlement of the concrete and formation of a film of water on the surface ("bleeding")

Plastic shrinkageReduction in volume during the plastic phase, due to excessive evaporation of the mixing water, either after bleeding or via the pores.The risk isparticularlygreat in the caseof flathorizontal surfaces.

Early thermal shrinkageThe hydration of cement causes an exothermic reaction, which canlead to: - cracks due the large thermal gradient in the concrete unit (applicable to large units - thickness > 50 cm)- cracks caused by external constraints preventing the contraction of the concrete as it cools.

Dehydration shrinkageOccurs when a concrete with a low W:C ratio (<0.45) and a high cement content continues to hydrate. The water is consumed, the porous network is emptied and the concrete dries out.The drying out continues in the hardened concrete: it is then called dehydrationshrinkage.Reduction in volume caused by the surrendering of moisture to the atmosphere, followed by a contraction of the pores.

The only cracking acceptable in concrete is the functional cracking of

reinforced concreteIt must be stated that, when the rules are followed, the "normal" cracking of concrete is totally controlled, which means that the cracks will be of limited width. This cracking is necessary to ensure a satisfactory level of working for the steels.

1 – CRACKING / SHRINKAGE: DESCRIPTION OF THE MAIN TYPES OF SHRINKAGE

Sedimentation, segregation and formation of a film of

water (bleeding)

Crack over reinforcement, void under reinforcement

Limited evaporation:. little shrinkage only .

low tensile forces

High evaporation . considerable shrinkage

. high tensile forces

Fresh concrete

Sedimentation … bleeding

24 hours 2 – 3 daysGreen

concreteVery young

concreteYoung

concreteTime

Chemical shrinkagePlastic shrinkage

Shrinkage by auto desiccationShrinkage by evaporationThermal shrinkage

End of setting Hardened

concrete

2 hours


Page C 3

Presetting: 2 to 4 hours. Setting: 4 to 8 hours. Hardening: 8 to 50 hours. Long term: ≥ 50 hours

BLEEDING PLASTIC SHRINKAGE THERMAL SHRINKAGE DEHYDRATION SHRINKAGE

•Long period of vibration•Large thickness of fresh concrete

•Long time before setting

•Unstable suspension (lack of fine components, insufficient quantity of cement, excessive quantity of water, etc.)

•Structural units with a high surface/volume ratio

•Slow setting

•High dehydration

•Shape of the units (large sizes)

•Poor insulation of the formwork

•Type of cement (high hydration heat)

•High cement content

•High evaporation

•Important phenomenon for high-performance concretes (W:C ratio ~ 0.3) – endogenous shrinkage with no exchange with the outside (internal dehydration)

•Formulate the concrete properly (enough fines, limited W:C ratio)

•Accelerate setting (avoid slow setting)

•Vibrate well (but NOT the reinforcement)

•Cure effectivelyWIND = DANGER

•Use of polypropylene fibres for concretes particularly exposed to severe weather conditions

•Avoid slow setting

•Reduce the thermal gradient(cement with low heat release)

•Add additional reinforcementsif necessary

•Avoid thermal shock on striking formwork

•Enough joints

•Reinforce, if applicable, to distribute cracking

Never add extra water as it - Delays hardening- Increases evaporation

PRINCIPLES

FACTORS

1 – CRACKING / SHRINKAGE (contd.): SHRINKAGE OVER TIME…

OF

PREVENTION

CAUSES

AND

Typical plastic shrinkage cracks


Page C 4

Preponderant causes and factors

Chemical parameters (corrosive ions)

Exposure parameters (tides and fluctuations in sea level, freeze/thaw cycle, activation in high temperatures)

Mechanical parameters (abrasion)

Principles of prevention

Formulation with a sufficient quantity of a suitable cementCements suitable for sea water

Provide the correct cover to the reinforcement

A compact and low permeability concrete (Page G 12)

the use of super plasticisers or water-reduction additivesfor a relatively low W:C ratioOptimisation of the granular skeleton

Careful placing and curingAdequate vibration (Page G 5)

Effective curing (Page G 8)

Phenomenon of sea water attack

Action of chlorides (corrosion, etc.)(Page C 16)

Action of sulphates (Page C 12)

Action of CO2 (carbonation) (Page C 15)

Attack conditioned by alternating wet / dry (inter-tidal zone) and the temperature of the water

2 – MARITIME ENVIRONMENT


Page C 5

Preponderant causes and factors(occurring in combination)

Potentially reactive aggregateActive alkalisRelative humidity (external environment) > 70 -

80%

3 – ALKALI REACTION

Phenomenon of alkali reaction

Symptoms (appearing within 2 to 10 years)Cracking: the cracks are progressive and they can open up by 0.5 mm/yearExudations, pustules or craters, colouration or discolouration, movements and deformation

of the construction

Tests to determine the risk of damage by alkali reaction may extend over several months.

silica

water

alkalis

Formation of an expansive gel

Cracking expansion


Page C 6

The risk of reactivity is greater with cements in the CEM I and CEM II ranges, while cements with a high slag content are an excellent way of inhibiting the reaction

In certain cases where there are potentially reactive aggregates, it would be totally unreasonable to send for non-reactive aggregate if there are other means of protection.

The use of CEM III/C, for other reasons than resistance to corrosive water and low exothermic heat, has protected constructors and clients from numerous problems.

Ash is an excellent means of protection, as is silica fume: they may either be added to the cement or directly to the concrete. There are two ways of judging whether there is a sufficient quantity of mineral additions: either by the performance test or by an alkali balance sheet.

Environment classClass 1 (XC1)

dry or slightly damp environment

E.g.:•Inside residential or office buildings•Constructions protected from adverse weather and condensation•Drained ground slabs•Units thicker than 50 cm

Class 2 (XC2 to XC4)damp environment (humidity >80% or in

contact with water)E.g.:•External sections (whether exposed to frost or not)•Sections in contact with non-corrosive ground and/or water (whether exposed to frost or not)•Internal sections where humidity is high (and whether exposed or not to frost)

Class 3 (XF1 to XF4)

damp environment with frost and de-icing

products

E.g.:•Internal and external sections exposed to frost and to de-icing salts

Class 4 (XS1 to XS3)marine environment

E.g.: •Units completely or partially submerged in seawater or splashed by it (and whether exposed to frost or not)•Unit exposed to air saturated with salt and to frost

Type of construction

I Non-load-bearing units Risk of appearance of minor or acceptable damage A A A A

II Risk of appearance of scarcely tolerable damage most buildings and civil engineering constructions A B B B

IIIRisk of appearance of scarcely tolerable damage

Exceptional constructions, nuclear power stations, prestige monuments, etc.

C C C C

A: No checks necessary

B: 6 possible ways of acceptingthe concrete formulation.

See proposed concrete formulation diagram belowC: use of non-reactive aggregate(potentially reactive aggregate subject to conditions: The recommendations of the French LCPC laboratory introduce, in prevention method C, a suggestion of avoiding reactiveaggregates, with the possibility of using cements with a high slag content.)

3 – ALKALI-REACTION (contd.): FRENCH RECOMMENDATIONS

Does the study show

that the aggregate is

non-reactive?(see next page)

Does the formulation one

of the criteria on the alkali

balance sheet?(LCPC

recommendations, chapter 5*)

Does the formulation meet an

expansion test performance

criterion?(performance test:

NF P 18-454Period of 3 to 5

months)

Does the formulation have

sufficiently convincing use references?**

Does the concrete contain

a sufficient proportion of

additions?(LCPC

recommendations, chapter 8*)

Have the particular

conditions for potentially

reactive aggregates been met?

(LCPC recommendations,

chapter 9*)

THE CONCRETE FORMULATION IS ACCEPTED

THE CONCRETE FORMULATION MUST BE MODIFIED

PROPOSED CONCRETE FORMULATION

YES TO ONE OF THE 6 QUESTIONS NO TO ALL THE QUESTIONS

* The recommendations relating to protection against the phenomena of alkali-reaction are contained in a document published by the LCPC in June 1994 entitled: Recommendations for protection against damage caused by alkali-reaction** The validation of the formulation by means of use references requires an accurate analysis of constructions carried out more than10 years ago in the region


Page C 7

3 – ALKALI-REACTION (contd.): GENERALAGGREGATE CHARACTERISATION PROCESS

Aggregate identification

Petrographic study

Screen test

Long-term test

Carbonated rockwhere SiO2 < 4%

Relative mineralspecies < 4%

Flint > 70%

40% < Flint < 70%

Qualification following the test

Expansion > Threshold

PR

PR

PRP

NR

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

*

*) If the PR qualification is considered to be sufficient, the procedure may be stopped

Screen test: this is a test that uses a greatly accelerated procedure capable of diagnosing, in less than one week, the reactivity of the alkalis in an aggregate which is non-reactive, potentially reactive or potentially reactive with a Pessimum effect.Reference method: accelerated autoclave test on mortar (5 days)Alternatives: Accelerated "Microbar" test; Chemical kinetic test

Long-term test: this is a diagnosis procedure which, although accelerated in comparison with the reaction kinetics observed on constructions, is sufficiently close to actual conditions to take into account the effective sensitivity of the aggregates. Principle: Expansion test on concrete samples (measurements taken at: 1 month, 2 months, 3 months, 4 months, 6 months and 8 months)

NR: Non-reactiveName given to aggregates for hydraulic concretes which, whatever their conditions of use, will not cause alkali-reaction problems

PR: Potentially reactiveName given to aggregates likely, under certain conditions, to cause alkali-reaction problems

PRP: potentially reactive with a Pessimum effectName given to aggregates which, although rich in reactive silica, can be used with no risk of problems, provided that their use meets theconditions described in the document "Recommendations for protection against damage caused by alkali- reaction"


Page C 8

France United Kingdom

LCPC 1994: Recommendations for protection against damage caused by alkali-reaction

BS 812-104: Testing aggregates. Method for qualitative and quantitative petrographic examination of aggregates

XP P 18-594, Aggregates - Alkali reactivity test method BS 812-123: Testing aggregates: Method for determination of alkali-silica reactivity. Concrete prism method

FD P 18-542, Aggregates - Qualification criteria for natural aggregates for hydraulic concrete in respect of alkali

reaction

BS 7943: Guide to the interpretation of petrographical examinations for alkali-silica reactivity

NF P 18-454, Concrete - Reactivity of a concrete mix in respect of alkali reaction - Performance test

3 – ALKALI-REACTION (contd.): NORMATIVE TEXTS FRANCE AND GREAT BRITAIN

United Kingdom – BRE Centre for Concrete ConstructionAlkali silica reaction in concrete

Internet site: www.bre.co.uk/

BRE Digest 330 Part 1Background to the guidance notes

BRE Digest 330 Part 2Detailed guidance for new construction

BRE Digest 330 Part 3Worked examples

BRE Digest 330 Part 4Simplified guidance for new construction using normal

reactivity aggregates


Page C 9

3 – ALKALI-REACTION (contd.): AMERICAN NORMATIVE TEXTS

Name of the test Period of the test CommentsASTM C227: Standard Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar

Method)

Varies: first measurement at 14 days, then at 1, 2, 3, 4, 6, 9 and 12 months, then every 6 months

The test must not cause significant expansion of carbonated aggregates. Long test period. The expansion is not necessarily caused by the alkali

reaction of the aggregate

ASTM C289: Determination of the silica alkali reactivity of aggregates (chemical

method)24 hours Rapid results. Certain aggregates give low expansion, even if they have a

high silica content. Not very reliable

ASTM C294: Natural mineral components of aggregates

Short period - as long as the visual examination takes

These descriptions are used to characterise the natural minerals forming the aggregates' sources

ASTM C295: Petrographic examination of the aggregates in the concrete

Short period - visual examination, not requiring long test periods

Generally includes an optical microscopy. May also include an X-ray, thermal or infra-red analysis - See ASTM C294

ASTM C441: Effectiveness of mineral or slag additions in concrete expansion prevention due to silica alkali reaction

Varies: first measurement at 14 days, then at 1, 2, 3, 4, 5, 9 and 12 months, then every 6 months

Highly-reactive artificial aggregate, may not represent real aggregatesPyrex contains alkalis

ASTM C856: Petrographic examination of hardened concrete

Short period - including the preparation of the samples and

the visual and microscopic examinations

Samples may be examined with a stereo microscope, a polarising microscope, a metallographic microscope and a scanning electron

microscope

ASTM C856: Uranium acetate treatment procedure Immediate results

Identifies small quantities of gel which may or may not cause expansionOpal, a natural aggregate, and carbonated paste may light up - the results

must be interpreted accordinglyThe tests may be supplemented by a petrographic examination and a

physical test in order to determine the expansion of the concrete.

ASTM C1260 Potential alkali reactivity of aggregates (mortar bar method) 16 days

More rapid alternative to ASTM C227Used for aggregates reacting slowly or those whose expansion is delayed in

relation to the reaction

ASTM C1293: Determination of Length Change of Concrete Due to Alkali-Silica

Reaction (concrete prism test)

Varies: first measurements at 7 days, then 28 and 56 days, then at 3, 6, 9 and 12 months, then

every 6 months

Requires a long test period to give significant resultsTo be used to supplement ASTM C227, C295, C289 and C1260

ASTM C1567: Potential Alkali-Silica Reactivity of Combinations of

Cementitious Materials and Aggregate (Accelerated Mortar-Bar Method)

16 daysMore rapid alternative to ASTM C1293

Used for aggregates reacting slowly or those whose expansion is delayed in relation to the reaction


Page C 10

Freeze /thaw phenomenonAction of freeze/thaw cycles

•Increase in volume associated with the transformation of water into ice (in the order of 9%)•Pressures caused by the movement of internal water towards "freezing fronts"

Action of de-icing salts•Thermal shocks caused by the melting of the ice•Distribution of salts through the concrete

→ Cracking throughout the mass of the concrete caused by an internal frost pressure→ Disintegration of the surface layer, known as spalling, which results from a high thermal gradient close to the surface

SolutionCreating a sufficient quantity of micro-bubbles of air to act as "expansion" vessels

Principles of preventionAgainst frost

•Use an air entrainer (Page E 31) to prevent excessive pressures. Important factors: the size of the bubbles and the distance between them.

Against de-icing salts•Use a high-quality concrete•Carry out its placing carefully (vibration and surface finish)

Design of the concrete•Air entrainers MUST be used •Use non-frost-susceptible aggregates•Avoid the use of sands that encourage bleeding (hollow sands and sands containing mica)•High class of mechanical strength

Installation•Production: vigorous mixing, carried out at high speed for a sufficient length of time•Transport: avoid prolonged waiting before placing, which may affect the air content•Placing: regular and uniform vibration (→ to break up large unstable bubbles)•Curing and hardening: protect the concrete from heat, dehydration and the cold as it sets and hardens

•In hot weather, young concrete must be kept damp.•In cold weather, the concrete must be protected and, if applicable, kept at a temperature of at least 10°.

•A long period of maturing is recommended before exposure to frostDesign of the constructions

•Reinforcement cover to be maintained•Facilities for collecting water to be provided• Provide falls to prevent standing water

4 - FREEZE / THAW


Action of freeze/thaw cycles Action of de-icing salts

Crater formed in the surface of the concrete by the bursting of frost-susceptible mortar

Frost-susceptible aggregatesurrounded by mortar

The freezing of the water contained in the aggregate causes it to expand and

creates pressure on the mortar

The expansion of the aggregate causes it and its surrounding mortar to burst

Samples subjected to 150 freeze/thaw cycles

Concrete with no entrapped air & high water/cement ratio

Concrete with entrapped air & low water/cement ratio

Without entrapped air Increasing % of entrapped air With

entrapped air


Page C 11

4 – FREEZE / THAW (contd.): MAIN NORMATIVE TEXTS

FranceLCPC 2003 - Recommendations for the durability of hardened concretes subjected to frost

XP P 18-420, Concrete - Spalling test on the surfaces of hardened concrete exposed to frost in the presence of saline solutions

XP P 18-424, Concrete - Freezing test on hardened concrete - Freezing in water - Thawing in water XP P 18-425, Concrete - Freezing test on hardened concrete - Freezing in air - Thawing in water

FD P 18-326 Frost zones in France

United States

ASTM C666: Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing

ASTM C617: Standard Practice for Capping Cylindrical Concrete Specimens

ASTM C682: Standard Practice for Evaluation of Frost Resistance of Coarse Aggregates in Air Entrained Concrete by Critical Dilation Procedures

ASTM C672: Standard Test Method for Scaling Resistance of Concrete Surfaces Exposed to De-icing Chemicals

Russia

GOST 10060.0: Concretes - Method for the determination of frost resistance. General requirements

GOST 10060.1: Basic method for the determination of frost resistance

GOST 10060.2: Rapid method for the determination of frost-resistance by repeated alternated freezing and thawing

GOST 10060.3: Concretes - Dilatometric rapid method for determination of frost-resistance

GOST 10060.4: Concrete. Structure mechanical rapid method for the determination of frost resistance

GOST 26134: Concretes. Ultrasonic method of frost resistance determination


Page C 12

Preponderant causes and factors(normally occurring in combination)

Addition of permanent moisture (addition of water from outside of wetting/drying cycle)

Strong heating of the concrete as it hardensHigh sulphate contentHigh aluminate content

Phenomenon of sulphate reaction

Reactions of external origin = secondary ettringite Sulphates arising from:Soils subject to the decomposition of organic substances containing

sulphur (fertiliser, plants)

Soils containing gypsumor anhydrite (caution ifconcentration >5%)

Soils containing pyrites (possibility of oxidising into sulphatesin contact with air and moisture) in alluvial or clayey soils

De-icing saltscarried by underground water

Seepage water

Seawater

Waste water from industrial sites

→ Phenomenon of concrete expansion and damageReactions of internal origin = Delayed Ettringite Formation (DEF)Sulphates arising from the cement and other components (gypseousaggregates, sulphides in certain aggregates).

→ Phenomenon of micro-cracking then expansion

5 – SULPHATE ATTACK

Ettringite: salt that is formed as the cement sets or in the longer term in the presence of sulphates (e.g. calcium sulphate present in the cement, pyrite oxide contained in the aggregate); this formation is accompanied by large expansion, which can generally damage the relevant construction. Under a microscope, it appears in the form of fine overlapping hexagonal beads or as crystal clusters.

Principles of prevention against Delayed Ettringite Formation

Use components for the concrete that comply with the standards in order to limit the addition of sulphates

Limit the heating of the concrete in the heart of the structure to 60 – 70°C:Preferably, if possible, use a low exothermic cementAvoid an excessive cement contentReduce the temperature of the components of the concreteAvoid insulating concrete mixes and formwork in hot weatherUse systems to cool the concrete

Adapt the formulation of the concreteUse cements with a low aluminate content, if possible, with the addition of

slag and with a moderate alkali content (PM ES type in France, HSR elsewhere)Use mineral additions (slag, fly ash, etc.)If possible, avoid siliceous aggregates (quartz type)Test the reactivity of the concrete to sulphate attackAvoid the addition of water from outside during the life of the

constructionIf possible, adapt the shape of the construction (avoiding, for example,

zones where water is retained)Provide land drain systems around the constructionUse suitable water-proofing systems


Page C 13

Principles of prevention

A compact and low permeability concrete (Page G 12)

•Sufficiently high cement content•Low water content•Particle size including a sufficient quantity of fine elements

Suitable design of the construction•Avoid creating zones where water accumulates and stands, and where surface water will create run-off channels

Careful placing•Suitable and homogenous vibration (Page G 5)

•Effective curing to avoid excessive early concrete dehydration (Page G 8)

•Monitor temperature and humidity during placing and on the following days


Natural water (pure water < fresh water < acid rain): corrosiveness will depend on three inter-dependant parameters: the pH, the hardness and the CO2content

Mineral and organic acids:•Natural water: in peat bogs and marshland, humic acids may reach high concentrations. •Industrial environments and associated effluent•Sewage systemsSugar (even if it is not acid)

Phenomenon of acid attack

Concrete is of a highly basic nature. It can, therefore, have a certain susceptibility to acid solutions:

External environment (acid) + concrete (base) → salt + water

This reaction will have an adverse effect on the proper behaviour of the concrete. In addition, if the salt is soluble

there is risk of damage by dissolving and leaching.

Dissolving and leaching

Increase in porosity and permeability

Increase in processes of deterioration

Loss of mass

Loss of alkalinity

Drop in strength and

rigidity

6 – ACID ATTACK

acid salt


Page C 14

Phenomenon of the corrosion of the reinforcement

Under normal conditions, the reinforcement encased in the concrete is protected against corrosion by the phenomenon of passivation (protective skin on the surface of the metal)

Two main phenomena may, under certain conditions, neutralise this protection and allow corrosion of the reinforcement to start:-The carbonation of the concrete by carbon dioxide in the air (Page C 15)

-Penetration of chloride ions down to the level of the reinforcement (Page C 16)

The cover to the reinforcement and the characteristics of the concrete encasing it are the fundamental parameters in controlling the durability of the constructions against corrosion phenomena and therefore their service lifespan.


- W/C ratio- Proportion of cement- Curing- Compacting

Permeability

Diffusion of chemical species from

the outside

Cracks

Thickness of cover

HumidityInfluence if HR>80%

Corrosion of the reinforcement

Concrete cover

Principles of preventionUse a compact and low permeability concrete (Page G 12)

Comply strictly with the statutory concrete cover thicknessConstruction detailing

• Avoid build-ups of water • Pay attention to the layout of the bars nearcorners, to prevent corrosive agents penetratingfrom 2 directions

Particular detailing for very corrosive environments• Cathodic protection This enables a metal to be protected from corrosion. The basic principle is to convert the potential of a metal to a level known as passivation. In order to modify the potential of the metal to be protected cathodically, an anode is used, installed in the same electrolyteAn onerous process, applied only to constructions at serious risk• Corrosion inhibitorsChemical that prolongs the passivity of the steel in the concrete in the presence of corrosive elements• Coverings for the reinforcement• Stainless steel reinforcement

Normalenvironment (CO2)

Contamination by chlorides

As an example, an increase in the minimum reinforcement cover of 10 mm would increase the lifespan of a construction from 50 to 100 years.

7 –CORROSION OF THE REINFORCEMENT (Consequence of carbonation and chloride attack)

Limit states

Depassivation of reinforcement

Exposure time

Incubation period

Formation of cracks

Spalling of the concrete

Destruction of structure due to the reduction of nett section and/or loss of adhesion

Propagation period

Incubation period

Propagation period

Stages in the corrosion of the reinforcement


Page C 15

Phenomenon of carbonation

In the presence of carbon dioxide in the air, the lime released by hydration (portlandite) carbonates. The basic environment (pH 12 to 13) becomes progressively modified and reaches a pH in the order of 9, which no longer provides protection for the reinforcement and leads to the depassivation of the steel, followed by the formation of expansive rust.

The speed of propagation of carbonation reduces with depth.

The relative humidity of the air plays,in particular, an important part: the speedof carbonation is at its maximum at arelative humidity in the order of 60%,but is negligible in a dry orsaturated atmosphere.


Environments:Carbonation takes place anywhere, but is more accelerated in towns and industrial environments, where pollution causes high concentrations of CO2

Factors:-Excessive porosity of the material in the surface zone -Insufficient cover to reinforcement

The depth of carbonation can be measured by a phenolphthalein colouring test

Principles of protectionRefer to the principles of protection against corrosion (Page C 14)

8 – CARBONATION

Effect of the relative humidity of the air on carbonation

Degree of carbonation

Non-carbonated regions are

coloured red or mauve and the

carbonated surfaces remain

unchanged

Carbonated concrete

Carbonation front

Non-carbonated concrete

reinforcement

Progression of the carbonation


Page C 16


Internal origin: basic components introduced when mixing the concrete (using chlorinated additives, seawater for mixing, contaminated aggregates)

External origin: Immediate surroundings of the construction-Exposure to marine spray / seawater-De-icing salts- Etc.

Phenomenon of chloride attack

The chloride ions may migrate by diffusion to the inside of the concrete, pass through the reinforcement cover zone, reach the reinforcement, attack the passive layer and cause corrosion, initially locally, which then spreadsto the whole surface ofthe steel.

The higher the chloride concentration around the reinforcement the faster the speed of corrosion.

The speed of corrosion will also depend on the concrete's porosity. It decreases with the W/C ratio.

In practice, it is important to restrict the quantity of chloride in the concrete

Laboratory tests suggest that corrosion starts to spread at a concentration of chloride ions in the order of 0.5% by weight ofcement.

Principles of prevention against the action of chloridesRefer to the protection measures against corrosion (Page C 14)

9 – CHLORIDE ATTACK

Corrosion of the reinforcing steel caused by chlorides

water

oxygen

« pinhole »corrosion


Page C 17

Nature of facing defectsDefects in shape which only affect appearance, are

slight unevenness, inclusions, lack of flatness. Those defects that affect both appearance and durability are major unevenness, chips, spalling, cracks, bruises. In all cases,they result in insufficient protection of the reinforcement

Defects in texture (surface irregularities) which only affect appearance are as follows: slight bubbling, bleeding, orange peeling, crazing, powdering, spalling. On the other hand, major bubbling, porosity, honeycombing and laitance leakage are defects in texture which affect both appearance and durability.

Defects in colour are those to which users are most sensitive. These include the outlines of visible aggregate, black stains, variations in shade, rust stains, marbling, dirt (writing, graffiti), efflorescence, which are evidence of improper use of the concrete.

Principles of preventionConcrete mix: use a compact and low permeability concrete (Page G 12)

Use clean sands and aggregates from uncontaminated sourcesDo not allow excess water to be usedUse specific additives (water reducers, super plasticisers, etc.)

Production and placing of the concreteAdapt the mixing to the compositionDo not allow additional water to be addedComply strictly with the specified concrete cover thicknessesCheck the watertightness of the formwork (abutments and props) and its resistance to

hydrostatic thrustDo not allow the concrete to drop too farVibrate so as obtain the best compaction and avoid segregationProtect the fresh concrete from wind, sun and frostFollow the formwork striking cycles

Suitable design of the construction (Page G 25)

Avoid hollows where water can collect or run offTake into account the direction that the facework faces

Preponderant causes and factorsThe most frequent causes of defects in appearance are of 3 orders:

Badly-designed or badly-selected proportions of the concrete's componentsThe formwork (poor choice of materials, sealing, wedging, skin preparation,

striking)The vibration of the concrete (unsuitable frequency, length of time and

application)Other factors, such as the processes and speed of concreting, weather conditions, or the curing of concrete without formwork or once the formwork is struck must not be neglected, but are seen less often as causes of major defects: they are aggravating factors.

10 – SURFACE APPEARANCE

ARCHITECTONICCONCRETE

Page G 19


Page C 18

10 – SURFACE APPEARANCE: ILLUSTRATIONS OF VARIOUS DEFECTS

Bubbling

Spalling

Honeycombing Bleeding of fresh concrete

Iron oxide stains

Sand streaking


Page C 19

10 – SURFACE APPEARANCE (contd;)

Monday's surprise with Friday's wall!!!

Monday: Wall 1 is shuttered and concretedTuesday: Wall 1 is struck, then wall 2 is shuttered and concretedWednesday, Thursday, Friday: …Saturday and Sunday: A rest after a busy weekThe following Monday: Wall 5 is struck and…. The colour of the finish is differentMoral: Allowance must be made for work stoppages at weekends and on public holidays

Polishing

Washing

Sand blasting

As cast

Bush hammering

Monday (1)

Tuesday (2)

Wednesday (3)

Thursday (4)

Friday (5)

The effects of surface treatments on durability may be classified in the following way (in decreasing order, i.e. from the most effective treatment to the least effective)


Page C 20

Design of the concrete Cracking Action of frost and de-icers

Corrosion of reinforcement

Chemical attackMarine environment

Components of the concrete

Cement Quantity, fineness, speed of setting

Depending on the severity of the frost-

susceptible environment, follow the

specifications for cement quantities

Choice depending on the environment's

level of corrosiveness (composition)

Aggregates Dimensions Frost-proof

Dimension depending on reinforcement

cover

Particular, choice depending on type of

attack

Additives which prevent dehydration

Air entrainer creating an effective system of

bubbles

plasticiser, waterproofing

Concrete W:C <0.50 or 0.4 depending on circumstances < 0,50

Installation

Production Effective mixing - transport time

Placing Regular vibration to ensure correct cover to the reinforcement

Curing Essential for all horizontal surfaces

Construction requirements

Creation of jointsReinforcement to prevent cracks

Avoid standing waterProvide means of

drainage

Thickness of reinforcement

cover

APPENDIX – SUMMARY OF THE ESSENTIAL CRITERIA FOR A DURABLE CONCRETE


Page D 1

PART D: NORMATIVE AND CONTRACTUAL CONSTRAINTS

1 – NORMATIVE CONSTRAINTS

1-1 – EUROPE…………………………………………..Page D 2

1-2 – USA………………………….…………………….Page D 3

1-3 – RUSSIA……………………………………….......Page D 4

1-4 – OTHER COUNTRIES…………………… ……..Page D 4

2 – CONTRACTUAL CONSTRAINTS…………………… ....….Page D 4


Page D 2

European standards apply in all the countries listed below.

In these notes, the particular features of French and English requirements will be

explained

Relationship between EN 206-1 and the standards for

design and execution, as well as the standards relating to

components and test standards

1-1 – EUROPE

1 – NORMATIVE CONSTRAINTS

EN 206-1Concrete

EN 1992

Design of constructions in concrete

ENV 13670 -1Execution of constructions

in concrete

EN 197Cement

EN 450 Fly ash

for concrete

EN 13263Silica fume

for concrete

EN 1934-2Additives for

concrete

EN 12620Aggregates for

concrete

EN 13055-1Lightweight aggregates

EN 1008Mixing water for concrete

EN 12878Pigments for

colouring construction

materials

EN 12350Test on fresh concrete

EN 12390Testing hardened concrete

FRANCE UNITED KINGDOM

GermanyAustriaBelgiumDenmark

SpainFinlandGreeceIrelandIceland

ItalyLuxembourg

NorwayThe Netherlands-

PortugalCzech

RepublicSweden

Switzerland

EUROPE

NF(French Standard)

BS( British

Standard)

(Eurocode 2)


Page D 3

Main standards used for concrete:

-ACI: American Concrete Institute : The ACI develops the majority of the specifications not covered by the IBC.

- ASTM: American Society for Testing Materials: This is the main reference source for ACI as far as specifications of materials and standard tests are concerned.

A specification is a set of characteristics and requirements with which a product, process or service must comply. Specifications are not standards.

1-2 – USA

CODESUntil 1997, there were 3 main « model » codes used in the USA (UBC, SBC et NBC) In 1997, these 3 codes have been grouped

in one code, the IBC : International Building Code.Although, even to day, the 3 model codes are still in use.

STANDARDSThe codes are heavily making reference to Standards such as the

one published by ASTM and ACI or ANSI (American National Standard Institute) and NFPA (National Fire Protection

Association)

Note : ANSI coordinates the development and the use of the various codes and standards used in the USA and represents the

USA in the international standard organizations (ISO)


Page D 4

Russian standards relating to concrete components and test standards are grouped together in the GOST

1-3 – RUSSIA

Allowance must be made for the relevant standards in each country and for the political, historical and economic influences of other countries on these relevant standards (for example: Turkmen standards are very close to Russian standards; Hong Kong and Singapore use British standards, which may be supplemented, etc.)

Allowance must be made for contractual constraints, which may require additional specifications. They may sometimes be more restrictive than local standards, whether in respect of the durability of the concrete, seismic constraints, the quality of facework, permissible deformation, etc.

1-4 – OTHER COUNTRIES

2 – CONTRACTUAL CONSTRAINTS


Page E 1

Part E: MATERIALS AND CONCRETE

1 – AGGREGATES………………………………………………………………...Page E 2

2 – CEMENT……………………………………………………………………….Page E 12

3 – ADDITIVES…………………………………………………………………….Page E 26

4 – MIXING WATER……………………………………………………………….Page E 34

5 – CONCRETE………………………………………………………………..….Page E 35

6 – CHECKS ON CONCRETE: MAIN NORMATIVE TEXTS………………...Page E 50

APPENDIX – MAIN WORLDWIDE MATERIALS SUPPLIERS………………Page E 54


Page E 2

1 - AGGREGATES

1-1 – MINERALOGICAL NATURE …………………………………..Page E 3

1-2 – HIGH SULPHATE, SULPHIDE, CHLORINE CONTENT ……Page E 4

1-3 – SHAPE OF THE GRAINS…………………………………….....Page E 5

1-4 – GRANULARITY………………………………………………….Page E 6

1-5 – CLEANLINESS OF THE AGGREGATES………………………Page E 7

1-6 – WATER AND POROSITY……………………………………...…..Page E 8

APPENDIX 1 – SELECTION CRITERIA DEPENDING ON THE USE OF THE CONCRETE… Page E 9

APPENDIX 2 – MAIN NORMATIVE REFERENCES ………………………………………..……Page E 10


Page E 3

Mineralogical origin Properties Difficulties

encounteredPossibility of use for

concrete

Eruptive or magmatic rocks: volcanic and plutonic rocks

GranitesHard and compact;

good frost resistance

Yes, mostlyDiorites

Porphyrites

BasaltsMetamorphic rocks: this includes any pre-existing

rock

Quartzites Hard and compact; chemical resistant

High quality aggregates used for

faceworkMarbles Yes

Shales Frost-sensitive Existence of friable fines Only hard shales

Gneiss Yes, if stableSedimentary rocks: this covers the surface of the continents and the

bottoms of the oceans

Limestones Good adhesion to mortar Yes

Dolostones Prior tests

Most aggregates are suitable for concrete

Unfavourable influence of clays, marly limestones

(expansion and long-term changes)

3 types of aggregates:•Natural: of mineral origin, obtained from loose or massive rocks, having been subjected to mechanical transformation only•Artificial: of mineral origin resulting from an industrial process including thermal or other transformations •Recycled: obtained by processing an inorganic material previously used in construction, such as concrete from building demolition

Origin of "extraction"•Rolled alluvial aggregates (shape acquired by erosion). For concrete, they are usually siliceous, calcareous or sand-limes•Quarried aggregates of angular shapes (obtained by blasting and crushing). In order to select this type of aggregate, consideration must be given to: the origin of the rock, the regularity of the bed, the degree of crushing, etc.)

1-1– MINERALOGICAL NATURE

MINERALOGICAL NATURE


Page E 4

HIGH SULPHATE, SULPHIDE AND

CHLORIDE CONTENT

Reaction with cement, cracking, corrosion of the

reinforcement

Chloride ion content: chlorides modify the kinetics of the hydration of the cement and cause the reinforcement to corrode. The chloride content arising from all the concrete’s components is therefore limited.

Reactivity to alkalis: In unfavourable conditions (aggregates containing a significant fraction of soluble silica in an alkali-rich environment) and in the presence of moisture, alkali reaction phenomena may cause the concrete to expand. (Page C 5)

Sulphur and sulphate content: Aggregates may contain small quantities of sulphates and sulphides (in France: Total sulphur content <0.4% by mass and sulphate content <0.2%).The sulphides present in the aggregates may oxidise and become sulphates, which may lead to expansion phenomena. The sulphates may interfere with setting and with the action of the additives.

1-2 – HIGH SULPHATE, SULPHIDE, CHLORINE CONTENT


Page E 5

SHAPE OF THE GRAINS,

ANGULARITY

Certain crushed sands may sometimes

adversely affect the placing of the concrete

and its final compactness.

Granular class: Aggregates are described according to their granular class d/D (where d is the smaller dimension and D the greater dimension). The granular categories are specified by using sets of different-sized sieves (en mm).

Flatness test A: The flatness factor characterises the shape of the aggregate on the basis of its largest dimension and its thickness. The higher the value of A, the more flat elements the gravel contains. A poor shape has an effect on consistence and encourages segregation.

Fineness modulus MF: This is equal to 1/100th of the sum of the cumulative sieve oversize, expressed in %, on various sieves. The lower the fineness modulus, the finer the sand.

Fines: D ≤ 0.063 mm

Sands: D ≤ 4 mmGravels: d ≥ 2 mm and D ≥ 4 mm

1-3 – SHAPE OF THE GRAINS, ANGULARITY

Influence of the granulometric compactness on the compactness of the granular mixture and on the consistence of the concrete

1 – Gravel dominant: the high level of friction forces reduces consistence2 – Maximum compactness: Consistence close to optimum3 – Sand dominant: The high quantity of water required for dampening leads to a reduction of consistence

Gravel

Sand


Page E 6

This is determined by sieving and is expressed as the percentage by mass of the aggregate passing through a specified set of sieves. The proportion of particles retained by a sieve is called the sieve oversize, the remainder the undersize.

It is represented by a granulometric graph representing the sizes of the sieves on the X-axis and the percentages of the cumulative undersizes passing through the successive sieves on the Y-axis.

GRANULARITY

This represents the dimensional

distribution of the grains contained in

an aggregate.

The implementation method may have an

influence on granularity (e.g. pumping)

The composition of the concrete generally requires discontinuousgranularity.Most concretes are mixed using 2 categories. This formula enables the storage of a large number of granular categories to be limited, as only 2 standard categories are required from aggregate producers.Continuous granularity (with 3 or more aggregates) requires moreaccurate batching and installations that can only be considered for large sites or for ready-mix concrete manufacturing plants.

1-4 – GRANULARITY

Range of aggregate sizes used in concrete

Sand with a majority of fine

grains

Normal sand

Fairly coarse sand

3/10 continuous

gravel

5/30.5discontinuous

gravel

Granulometric analysisunderflow

sands gravels pebbles

rejection

fine medium fcoarse

discontinuity


Page E 7

For gravel: Given by the percentage passing through a 0.5 mm sieve (sieving carried out under water)

For sands: Provided by the "sand equivalent test" which enables the proportion of clay in the material to be measured. The higher the SE (cleanliness) value, the cleaner the sand

This may also be evaluated by the methylene blue test(VB). The lower the VB value, the cleaner the sands.

CLEANLINESSOF AGGREGATES

Cleanliness refers to an absence of

undesirable fine elements (e.g:

clayey fines) in the aggregates

Impurities interfere with the hydrationof the cement and cause

defects in aggregate / paste adhesion, which may have an

effect on the strength of the concrete

1-5– CLEANLINESS OF THE AGGREGATES

Clean sandPS = 93 PS = 78

Polluted sandPS = 53

H1 = 7.3

H2 = 7.8

H1 = 7.2

H2 = 9.2

H1 = 8

H2 = 15

Water Flocculate Sand


Page E 8

Apparent density: mass of dry aggregate occupying the unit of volume. It depends on the settlement of the grains. Example: rolled calcareous silicate aggregates- Apparent: ~ 1400 to 1600 kg/m3

- Absolute (excluding voids between grains): 2500 to 2600 kg/m3

Porosity: represents the ratio of the volume of voids contained in the grains to the volume of the grains, as a percentage. The porosity of typical aggregates is generally very low. It is high in the case of lightweight aggregates.

Water absorption factor Ab: represents the water absorption capacity of an aggregate. The higher it is, the more absorbent the material is.

WATER AND POROSITY

The water content of aggregates stored on site must be known, in order to calculate the amount

of water to be added when the concrete is

mixed.

Sands expand (increase in volume reaching up to 20 to 25%) at water contents of 4 to 5%. The quantity, if calculated by volume, must be corrected.

1-6 – WATER AND POROSITY


Page E 9

Nature of the concretes and of the construction Nature of the aggregates Density of the

concrete

Traditional concrete for site or prefabrication plant

All rolled or crushed aggregates, with a preference for siliceous, calcareous

or sand-limes

2200 to 2400 kg/m3

Exposed, architectonic concrete

The same, but also porphyrites, basalts, granites, diorites, which

provide a very rich palette of appearances and colours

2200 to 2400 kg/m3

Road uses All of rolled or crushed origins 2200 to 2300 kg/m3

Lightweight

concretes

for structures Expanded clay or shale, expanded slag

1500 to 1800 kg/m3

semi-insulatingsemi-load-

bearingExpanded clay, pozzolana, pumice 1000 to 1500

kg/m3

Insulating Vermiculite, cork, timber, expanded polystyrene, expanded glass 300 to 800 kg/m3

Dense concrete Corundum, barytine, magnetite 3000 to 5000 kg/m3

Refractory concrete Corundum, refractory product waste, special aggregates

2200 to 2500 kg/m3

Concrete or screeds for industrial slabs

(subject to high abrasion)

Corundum, carborundum, metal aggregates

2400 to 3000 kg/m3

APPENDIX 1 – SELECTION CRITERIA DEPENDING ON THE USE OF THE CONCRETE


Page E 10

APPENDIX 2: MAIN NORMATIVE REFERENCES

French standards British standards

NF EN 12630: Aggregates for concrete BS EN 12620: Aggregates for concrete

NF EN 1305-1: Lightweight aggregates - part 1: lightweight aggregates for concrete and mortar

BS EN 13055-1: Lightweight aggregates - Part 1: Lightweight aggregates for concrete, mortar and grout

XP P 18-545: Aggregates: elements for definition, conformity and codification

PD 6682-1: Aggregates - Part 1: Aggregates for concrete Guidance on the use of BS EN 12620

Series NF EN 933: Tests to determine the geometric characteristics of aggregates

PD 6682-4: Aggregates - Part 4: Lightweight aggregates for concrete, mortar and grout Guidance on the use of BS EN 13055-1

Series NF EN 1097: Tests to determine the mechanical and physical characteristics of aggregatesSeries NF EN 1744: Tests relating to the chemical properties of aggregates

Russian standards

GOST 5578: Slag crushed stone and slag sand of ferrous and non ferrous metallurgy for concretes. Specifications

GOST 8267: Crushed stone of rocks and gravel for construction works. Specifications

GOST 8735: Sand for construction work. Testing method

GOST 8736: Sand for construction work. Specifications


Page E 11

United StatesCharacteristics Signification and scope Test descriptions

Resistance to abrasion and damage

Quality index of the aggregates, resistance to wear of floors and

roads

ASTM C131: Standard Test Method for Resistance to Degradation of Small Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

ASTM C535: Standard Test Method for Resistance to Degradation of Large Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

ASTM C779: Standard Test Method for Abrasion Resistance of Horizontal Concrete Surfaces

Frost resistance Surface spalling, roughness and poor appearance

ASTM C666: Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing

ASTM C682: Standard Practice for Evaluation of Frost Resistance of Coarse Aggregates in Air Entrained Concrete by Critical Dilation Procedures

Resistance to disintegration by sulphates Resistance to weather conditions ASTM C88: Standard Test Method for Soundness of Aggregates by Use of Sodium Sulphate or Magnesium Sulphate

Shape and surface texture of particles Consistence of fresh concrete

ASTM C295: Standard Guide for Petrographic Examination of Aggregates for Concrete

ASTM D3398: Standard Test Method for Index of Aggregate Particle Shape and Texture

Particle size Consistence of fresh concrete, economy

ASTM C136: Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

ASTM C117: Standard Test Materials Finer than 75 µm Sieve in Mineral Aggregates by Washing

Density Calculation of mixes, classification

ASTM C29: Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate

ASTM C127: Standard Test Method for Density, Relative Density (Specific Gravity) and Absorption of Coarse Aggregate

ASTM C128: Standard Test Method for Density, Relative Density (Specific Gravity) and Absorption of Fine Aggregate

Absorption and surface moisture

Concrete quality control (water:cement ratio)

ASTM C128: Standard Test Method for Density, Relative Density (Specific Gravity) and Absorption of Fine Aggregate

ASTM C70: Standard Test Method for Surface Moisture in Fine Aggregate

ASTM C127: Standard Test Method for Density, Relative Density (Specific Gravity) and Absorption of Coarse Aggregate

ASTM C566: Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying

Compressive and bending strength

Acceptance of fine aggregates that have failed other tests

ASTM C78: Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third Point Loading)

ASTM C39: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens

Definition of components Proper comprehension and communication

ASTM C125: Standard Terminology Relating to Concrete and Concrete Aggregates

ASTM C294: Standard Descriptive Nomenclature for Constituents of Concrete Aggregates

Components of the aggregate Determining the quantity of harmful and organic materials

ASTM C142: Standard Test Method for Clay Lumps and Friable Particles in Aggregates

ASTM C123: Standard Test Method for Lightweight Particles in Aggregate

ASTM C117: Standard Test Materials Finer than 75 µm Sieve in Mineral Aggregates by Washing

ASTM 40: Standard Test Method for Organic Impurities in Fine Aggregates for Concrete

ASTM C87: Standard Test Method for Effect of Organic Impurities in Fine Aggregate on Strength of Mortar

ASTM C295: Standard Guide for Petrographic Examination of Aggregates for Concrete

APPENDIX 2: MAIN NORMATIVE REFERENCES


Page E 12

2 - CEMENTS2-1 – MANUFACTURE OF A CEMENT ………………………………………..…….Page E 13

2-2 – HYDRATION REACTION OF THE CEMENT ……………………………..….Page E 14

2-3 – EUROPE – EN 197-1 2-3-1 – Description of a typical cement ………………………………..Page E 152-3-2 – Additions…………………………………………………………….Page E 162-3-3 – French specifications .....………………………………………...Page E 172-3-4 – British specifications .....………………………………………..Page E 192-3-5 – Main European normative texts ………………………………..Page E 20

2-4 – USA2-4-1 – ASTM C150: Specification for Portland cement………………Page E 212-4-2 – ASTM C595: Specification for Blended Hydraulic cement….Page E 222-4-3 – ASTM C1157: Standard performance for hydraulic cement..Page E 222-4-4 – Summary table ………………………………………...…………...Page E 222-4-5 – SMC: Supplementary Cementitious Materials………………...Page E 23

2-5 – IMPORTANT NOTE: EUROPE / USA………………………………………..….Page E 24

2-6 – RUSSIA: MAIN NORMATIVE TEXTS RELATING TO CEMENTS ................Page E 25


Page E 13

80% limestone (CaCO3)20% clay (SiO2 – Al2O3)

Correctives: bauxite, iron oxide, slag, etc.

1 to 6%4 to 8%18 to 24%65 to 70%

Iron oxide(Al2O3)

Aluminium oxide(Al2O3)

Silica(SiO2)

Lime(CaO)

Chemical composition (weight)

62 2288

Tricalcium silicate or aliteDicalcium silicate or belite

Tricalcium aluminate Tetracalcium aluminoferrite

C3SC2SC3SC4S

average % by weight NameSymbolic

notation

4 main cristalline phases

Clinker + gypsum + other possible components: blastfurnace slag, fly ash,

limestone, silica fume

RAW MATERIALS

RAW

CLINKER

CEMENT

STAGES OF MANUFACTURE(dry process, the most common)

COMPOSITION

Crushing < 200 µm

Firing 1450°

Grinding <100 µm with gypsum

2-1 – MANUFACTURE OF A CEMENT

Limestone + clay

Additive product

gypsum

cement


Page E 14

2-2 – HYDRATION REACTION OF THE CEMENT

Water/cement ratioThe quantity of water is characterised by the water: cement ratio. The higher this ratio, the longer hydration will take and theweaker and less durable the concrete will be. However, the quantity of water can be greatly reduced if the concrete is heavily compacted and, especially, if plasticisers (water reducers) or super-plasticisers (significant water reduction) are used.When calculating quantities for the mix, the terms water: binder ratio (this is the mass of the water divided by that of the binders –Portland cement, composite cement, fly ash, slag, silica fume,, etc.) and water: cement ratio are often used indifferently to describe the proportion by weight of the water and the Portland cement or of the water and the composite cement.

The water forms a system of capillaries around the grains

Formation of tobermorite gel on the surface of grains

The capillary interstice reduce. Appearance of a certain stiffness of the

paste

The interstices are partially filled by the gel. The paste acquires strength

Strength continues to grow for as long as the gel continues to develop. Slow phenomenon and presence of water

necessary

Before setting

During mixing water

setting

Start of hardening

Subsequent hardening


Page E 15

CEM I to IV A, B or C M S, V, W, L , P, Q , T or LL, D 32.5 to 52.5 N or R CE

Cement families Quantity of Clinker

At least 2 main components other

than clinker

Names of the main components other

than clinker

Strength class at 28 days in

MPa

Sub-class of strength at 2

days

EuropeanStandard

CEM IPortland cement 95 to 100%

S: Ground granulatedblastfurnace slag

V: Siliceous fly ash

W: Calcic fly ash

L or LL: Limestone

D: Silica fume

P: Natural pozzolan

Q: Natural calcinated pozzolan

T: Calcinated shale

32.5(32.5 < Rc < 52.5)

Rav = 45 MPa

42,5(42.5 < Rc < 62.5)

Rav = 55 MPa

52,552.5 < Rc

Rav = 60 to 65 MPa

The strength of the concrete is

proportional to Rc i.e. fc = k Rc

According to the development of

the strength

N: Ordinary strength

development at 2 days

R: Rapid strength

development at 2 days

E.g.: 52.5 NRc2 ≥ 20 MPa

E.g.: 52.5 RRc2 ≥ 30 MPa

CEM IIBlended

Portland cement

A: 80 to 95%B: 65 to 79%

YesFor example M (S - LL)

CEM IIIBlastfurnace

cement

A: 35 to 64%B: 20 to 34%C: 5 to 19%

CEM IVPozzolanic

cement

A: 65 to 89%B: 45 to 64% Abroad

CEM VCement made

from slag and fly ash

A: 40 to 64%B: 20 to 38%

2-3 – EUROPE – EN 197-1

2-3-1 – Description of a typical cement


Page E 16

Main effects of the components added to the clinker

Components added

Main effects of the component added to the clinker

SGround

granulated blastfurnace slag

Reduces short-term reactivity. Reduces shrinkage.Slower increase in strengthSuitable for constructions in contact with the ground

P Natural pozzolanaReduces short-term reactivity and its effects Supplements hydration by consuming Portlandite

Q Calcinated pozzolana

V Siliceous fly ashProvides additional long-term strengthImproves durability by reducing permeabilityImproves consistence. Stains the concrete black

W Calcic fly ash Improves consistence. Stains the concrete black

T Calcinated shale Reduces short-term reactivity and its effects Supplements hydration by consuming Portlandite

L and LL Ground limestone

Accelerates the very short-term (2 to 7 days) kineticsSupplements the granular skeleton

M Mixture of components

Combines the effects of the various componentsReduces the price of the cement. Variable colour and properties

2-3-2 – Additives

From left to right: fly ash, metakaolin (calcinated clay), silica fume, fly ash, slag and calcinated shale


Page E 17

Main cements marketed in France

Main fields of use Particular precautions

CEM I

Reinforced or Prestressed Concrete CEM I category R: Rapid striking of formwork (prefabrication)CEM I 52.5N or 52.5R: High strength RC or PC Mechanical characteristics not suitable for standard masonry, mass concrete or lightly reinforced concrete

to be avoided for mass concrete construction due to the heat of hydration (excessive rise in temperature during execution)Caution if high risk of alkali reaction

CEM II

Suitable for mass concrete requiring a moderate rise in temperature.Category R: Works requiring higher initial strengthPM or ES: Works in corrosive environmentsCEM II 32.5: Masonry worksCEMII 32.5N and 42.5N: Any type of RC workCEM II 52.5: RC or PC

Caution if attractive appearance is important: Certain CEM II cements contain high proportions of components likely to cause very wide variations in colour, particularly fly ash.

CEM II/ A-S or B-

SCEM IIICEM V

Blastfurnace slag cements suitable for:- Hydraulic or underground construction, foundations, injection- Works in corrosive water: sea, selenitic, industrial and pure water; - Mass concrete works: foundations and dams- Works in an agricultural environment: storage, slurry and silage pits

Concretes (using these types of cement) that are liable to desiccation: keep damp during setting (curing and curing products); to be avoided for rendersDo not use this type of cement in cold weather as hydration slows down in the coldCEM V: take care when mixing with the additives.

For special works, use cements that have additional characteristics:In corrosive environments:

Cements for works in the sea (PM)Cements for works in water with a high sulphate content (ES)

For mass concrete construction: Cements with a low initial hydration heat (CP)

2-3-3 – French specifications


Page E 18

Special cements

Characteristics Main fields of use

CNP: Prompt Natural Cement

Rapid setting and very high short-term strengthResistant to corrosive water(selenitic water, pure water, acid water)There is a standard for works at sea: PM

Can be used for mortar and, if required, for concrete•Standard sealing, locking in position, filling holes, water courses, caulking•External wall renders (when mixed with natural limes), moulding•Small constructions: tie beams, inspection chambers, sills•Corrosive environments (pure water, sea water)•Works at sea

CA: High Alumina Cement

High short-term strengthResistant to corrosive environments and acids (up to a pH of around 4)There is a standard for works at sea: PM and in water with a high sulphate content: ESImplementation in cold weatherRefractory cement (up to 1300°C)

•Works requiring a high short-term strength•Concreting in cold weather (down to -10°C for mass concrete)•For concretes that are subject to thermal shocks of heavy abrasion•For concretes that have to withstand temperatures of up to 1250°C•Works at sea•Works in a highly and very highly corrosive environment: industrial environment, urban sewers and other drainage works

2-3-3 – French specifications (contd.)


Page E 19

Main cements marketed in the United Kingdom

Description Notation

Portland Cement I

Sulphate-resistant Portland cement SRPC

Portland cement + another component (Fly ash, ground granulated blastfurnace slag (GGBS), limestone) IIA

Portland cement + 21 to 35% of fly ash IIB-V or IIB-V+SR

Portland cement + 21 to 35% of GGBS IIB-S

Portland cement + 36 to 65% of GGBS III-A

Portland cement + 66 to 80% of GGBS IIIB or IIIB+SR

Portland cement + 36 to 55% of fly ash IVB or IVB+SR

Other cements for special uses:Sulphate-resistant cements: BS 4027 – Specification for sulphate-resisting Portland cement (SRPC)

Cements with low hydration heat: BS 1370 – Specification for low-heat Portland cement

2-3-4 – British specifications


Page E 20

2-3-5 – Main European normative texts

France Great BritainNF EN 197-1, Cement - Part 1: Composition,

specifications and conformity criteria for common cements

BS EN 197-1, Cement - Part 1: Composition, specifications and conformity criteria. Common cements

NF EN 196-2, Cement testing methods - Part 2: Chemical analysis of cement BS EN 197-2, Cement - Part 2: Conformity evaluation

NF P 15-314, Hydraulic binders - Prompt natural cement

BS EN 197-4, Cement - Part 4: Composition, specifications and conformity criteria for low early strength blast furnace cements

NF P 15-315, Hydraulic binders - High Alumina Cement

BS 915, Specification for high alumina cement

BS EN 14647, Calcium aluminate cement - Composition, specifications

and conformity criteria for calcium aluminate cement

FD P 15-316, Hydraulic binders - Use of high alumina cement in structural elements In the future, BS 915 will be replaced by BS EN 14647

NF P 15-317, Hydraulic binders - Cements for works at sea BS 1370, Specification for low-heat Portland cement

NF P 15-318, Hydraulic binders - Cement with limited sulphide content for pre-stressed concrete BS 4027, Specification for sulphate-resisting Portland cement

XP P 15-319, Hydraulic binders - cements for works in water with a high sulphide content

BS 6610, Specification for pozzolanic pulverised fly

ash cements

BS EN 14216, Very low heat special cements - Composition, specifications

and conformity criteriaIn the future, BS 6610 will be replaced by BS EN 14216


Page E 21

Specifications for cements in the USA are dictated by ASTM (American Society for Testing and Materials) standards, the main ones of which are:-ASTM C 150: Specification for Portland Cement-ASTM C 595: Specification for Blended Hydraulic Cement-ASTM C 1157: Standard Performance Specification for Hydraulic Cement These standards make a distinction between Portland cements and blended cements

Cements meeting ASTM C 150 are the most widely-available from cement manufacturers.It sets the physical and chemical characteristics to be met by the 5 types of Portland cement.This ASTM standard sets the content of the 4 main components of cement (C3S, C2S, C3A, C4AF, and composition of the clinker).

Type of cement Particular features

I General useII Moderate hydration heat and sulphate-resistanceIII High initial strengthIV Low hydration heatV High sulphate-resistance

IA, IIA or IIA Type I, II or III with air entrainerLA With low alkali contentI/II Mix of types I and II, but not referenced by ASTM

This ASTM standard only permits additions of calcium sulphate and air-entraining agents to the cements. Other additives may be used; their specifications are set out in standard C 495, which sets the permissible deviations in the properties of the cements in the event of addition.

2-4 – USA

2-4-1 – ASTM C150: Specification for Portland Cement


Page E 22

Contrary to the previous ASTM standards, which specify the composition of the various cements, this standard is based solely on the characteristics and the levels of performance of the cements. It therefore imposes no restrictions on their composition.There are 6 different types: GU, HE, MS, HS, LH, MH (see table)

General useModerate sulphate-resistance

Early strength Low hydration heat

Moderate hydration heat

High sulphate-resistance

With low alkali content

Portland CementASTM C150 I

II (sulphate-resistance as an

option)III IV II V LA as an option

Blended Hydraulic CementsASTM C505

ISIP, PI(PM)I(SM)

S

IS(MH)IP(MH)

I(PM)(MH)I(SM)(MH)

P(LH)

IS(MS)IP(MS)P(MS)

I(PM)(MS)I(SM)(MS)

LA as an option

Hydraulic cementsASTM C1157 GU MH HE LH MS HS Option R

These cements are much more widely-used in Europe. They are, however, gaining popularity in the USAThe American standard permits the use of pozzolan and slag in blended cements, provided thatthe specifications for pozzolanic activity are met(see table). In particular, the compressive strength of the blended cement must reach at least 75% of that of the reference Portland cement. This standard also specifiesthe physical and chemical specifications for the blendedcements. In addition, all these types of cement may be treatedto meet criteria: moderatesulphate-resistance (MS), air-entrainment (A), hydrationheat moderate (MH) or low (LH).

Type of cement Description Composition

IPP Pozzolanic cement 15-40% pozzolans (P: slower strength development

than type IP)

I(PM) Portland cement with pozzolans 0-15% of modified pozzolans (fly ash)

IS Blastfurnace cement 25-70% of blastfurnace slag

S Slag cement 70-100% of blastfurnace slag

I(SM) Portland cement with slag 0-25% of modified blastfurnace slag

2-4-4 – Summary table

2-4-3 – ASTM C1157: Standard performance specification for hydraulic cement for Portland cement

2-4-2 – ASTM C595 Specification for Blended Hydraulic cement


Page E 23

More than half of ready-to-use concretes contain fly ash, ground granulated blastfurnace slag, silica fume, etc. and other pozzolana additions. These additions are known as SCMs. They may be added to the mix, either by adding them when the water is added or as a component in a Blended Cement, or may be both at the same time.

2-4-5 – SCM: Supplementary Cementitious Materials (Additions)

Characteristics ASTM test name Comments

Fly ash and other pozzolans

ASTM C618: Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolana for Use as a Mineral

Admixture in Concrete

Classification:Type N: natural pozzolans

Type F: flyashType C: fly ash

Ground Granulated Blastfurnace Slag

ASTM C989: : Standard Specification for Ground Granulated Blast Furnace Slag for Use in Concrete

and Mortars

Silica fumeASTM C1240: Standard Specification for Use of Silica

Fume for Use as a Mineral Admixture in Hydraulic Cement Concrete, Mortar and Grout

For the properties of the admixtures, refer to the table on page E 16


Page E 24

Do not confuse CEM I, II, III, IV and V of EN 197-1 with cement types I, II, III, IV and V of standard ASTM C150.Caution, they have no connection with each other!!!!!EN 197 is not normally available in USA.

2-5 – IMPORTANT NOTE: USA / EUROPE


Page E 25

Cements

GOST 30515: Cements - General specifications

GOST 10178: Portland cement and blast Portland cement - Standards

GOST 969: Alumina and high alumina cements - Specification

GOST 22266: Sulphate-resisting cements - Specifications

GOST 965: Portland cements, white - Specification

GOST 11052: Gypsum-alumina expanding cement

GOST 15825: Coloured Portland cement - Specifications

Additions GOST 24640: Additions for cements - Classification

2-6 – RUSSIA: MAIN NORMATIVE TEXTS RELATING TO CEMENTS


Page E 26

3 - ADDITIVES

3-1 – CONSISTENCE OF THE CONCRETE3-1-1 – Plasticisers / Water reducers………………………………..Page E 273-1-2 – Superplasticisers………………………………………..…….Page E 273-1-3 – Properties, mix proportions, application, ………………...Page E 28

3-2 – SETTING / HARDENING3-2-1 – Setting / hardening accelerator………………………..…...Page E 293-2-2 – Setting retarders ……………………………………………..Page E 293-2-3 – Properties, mix proportions, application ………………...Page E 30

3-3 – PROPERTIES OF THE CONCRETE 3-3-1 – Air entrainer ……………………………………………………Page E 313-3-2 – Integral waterproofing ……………………………………….Page E 313-3-3 – Properties, mix proportions, application ……………......Page E 32

3- 4 – CHOICE OF TYPE OF ADDITIVE DEPENDING ON ITS PROPERTIES.Page E 33

3-5 – MAIN NORMATIVE TEXTS RELATING TO ADDITIVES…..Page E 33


Page E 27

The main function of these additives, in addition to consistence, is to cause an increase in mechanical strength by

a reduction in the water content of the concrete.

Added to a concrete, generally just before it is placed, their main function is to cause a major improvement in the

consistence of the mix.

Fields of application:All standard concretes up to 30 MPaReady-mix concreteConcrete for lightweight prefabricationConcrete for civil engineering structuresConcrete for roadsConcrete for civil engineeringAgricultural concrete

Fields of application:Concrete for prefabricationReady-mix concreteDense and lightweight concreteConcrete for civil engineering structuresConcrete for industrial slabsConcrete for use in building Prestressed concrete Pumped concrete Concrete for deep foundationsConcrete for heavily-reinforced constructionsConcrete subjected to a corrosive environmentHigh-performance concrete, very high-performance Concrete, ultra-high-performance concrete Self-levelling, self-placing concreteArchitectonic concrete

3-1 – CONSISTENCE OF THE CONCRETE

3-1-1 – Plasticisers / Water reducers 3-1-2 – Superplasticisers

These additives modify the rheological behaviour of the concrete, mortar or grout in its fresh condition, before it starts to set. They lower the shear threshold and modify its

viscosity.

cement Dispersed state of the cement

water

lump

Better hydratation

Grain of cement

Addition of plasticiser

Hydrarted surface

cement waterDispersed state of

the cement

lump

Hydrarted surface

Grain of cement

Better hydratation

Addition of superplasticiser


Page E 28

Water-reducing plasticisers Superplasticisers

Quantity used as a % of the mass of the cement Generally < 0.5% Generally 0.5% to 3%

Addition to the mixing water In the concrete before placing

Effect on the placing of the concrete At constant consistence, water reduction >6.5%At constant water/cement ratio, large improvement

in concrete fluidity; improvement in slump of at least 80 mm

Strength at all stages •Greater than that of control•Minimum increase of 10%

In comparison with control, slight reduction possible

Favourable secondary effects

•Increase in compaction, reduction in permeability

•Possible improvement in resistance of the concrete to corrosive chemicals

The use of such additives may enable high-performance concrete to be created, with a low

water/cement ratio

Other effects Possible slight increase in shrinkage

with with plasticiserplasticiserSlumpSlump

(cm)(cm)

W:CW:C

controlcontrol

"Fluidifying" effect at same W:C"Fluidifying" effect at same W:C

10

15

5

0,3 0,4 0,5 0,6

W:C=0.50W:C=0.50

W:C=0.50W:C=0.5020

Slump 6Slump 6

Slump 19Slump 19

SlumpSlump(cm)(cm) with with

plasticiserplasticiser controlcontrol

"Water"Water--reducing" effect at same consistencereducing" effect at same consistence

10

15

5

0,3 0,4 0,5 0,6

W:CW:C

W:C=0.50W:C=0.50W:C=0.34W:C=0.34

20

SlumpSlump(cm)(cm) with with

plasticiserplasticiser controlcontrol

Double effectDouble effect

10

15

5

0,3 0,4 0,5 0,6

W:CW:C

W:C=0.50W:C=0.50W:C=0.34W:C=0.34

W:C=0.50W:C=0.5020

W:C=0.42W:C=0.42

3-1-3 – Properties, mix proportions, application


Page E 29

The main function of a setting accelerator is to reduce the timetaken for the cement to start and end its set in the concrete.

The main function of a hardening accelerator is to accelerate the initial development and strength of the concrete.

Both the above functions are often linked.

Added to the mixing water, their main function is to increase the length of time before the cement starts to set in the concrete.

Fields of application:

Concreting in cold weatherManufactured concrete (blocks, paving slabs, pipes, etc.)Need for an increase in productivity (ready-mix or prefabrication)Rapid striking of formworkConcrete with high early strengthEtc.


Concreting in cold weatherLong-distance transport or pumpingMass concretingContinuous placing

3-2 – SETTING / HARDENING

3-2-1 – Setting / hardening accelerator 3-2-2 – Setting retarders

These additives are chemicals that modify the solubility of the various components of cements and, especially, the speed at which they dissolve

Setting accelerator

Reference concrete

End of settingStart of setting

Start of setting

End of setting

time

Reference concrete

End of setting

End of settingStart of setting

Start of setting

Setting retarder

time


Page E 30

Setting accelerators Hardening accelerators setting retarders

Quantity used/mass of cement 1 to 3% 0,2 to 3% 0.1 to 1%

Addition To the mixing water

Effect on setting Acceleration will vary, depending on mix proportion, types of cement and temperature

Very variable delays, depending on mix proportions, cement,

temperature

Effects on strength

Initial (before 3 days) Increased to 1 or 2 days Increased Reduced to 1 or 2 days

Final (before 28 days)

Slightly reduced (more so if setting has been

accelerated)

Unchanged or slightly reduced Slightly increased

Favourable secondary effects – – Improvement in consistence, with

possible water reduction

Other effects Possible slight increase in shrinkage –



Page E 31

Their function is to cause the formation of micro-bubbles of air in

the concrete, evenly distributed through the

mass. This characteristic improves the

consistence of the fresh concrete and its

frost-resistance.

The main function of integral waterproofing is to reduce the

capillary absorption of the concrete.

However, it should be remembered that it is unable

to make a poor or badly-proportioned concrete, or one

with large voids or lack of homogeneity, waterproof.


Civil engineering or building constructions required to be resistant to frost and/or de-icing salt

Concrete for roadsExtruded concrete (safety barriers, etc.)Spun concrete (beams, etc.)


Concrete for tanksConcrete in contact with surface waterPrecast concrete: paving slabs, decorative units

3-3 – PROPERTIES OF THE CONCRETE

3-3-1 – Air entrainer 3-3-2 – Mass waterproofing

WITHOUT mass waterproofing

WITH mass waterproofing

Water penetration


Page E 32

Air-entrainers Waterproofing

Mix proportion (mass of cement) 0.01 to 0.5% 1 to 3%

Freeze/thaw cycle resistance

Use recommendedWorthwhile improvement –

Resistance to atmospheric corrosion, CO2, maritime

atmospheresEffect varies

Improvement in resistance thanks to a reduction in air

permeability

Resistance to corrosive chemicals (selenitic water,

sulphated water, etc.)Possible improvement

Improvement, thanks to a reduction in the

permeability of the concrete

Favourable secondary effects

Improvement in surface finish –



Page E 33

Property Additives water-reducers plasticisers super

plasticisershardening

acceleratorssetting

acceleratorssetting

retarders air-entrainers integral

waterproofing

consistence + + +Setting time - +

Strengthin short term (3 days) + + + + - -

in long term (>28 days) + + = + -Entrained air +

Frost-resistance of the set concrete + +Compactness + + +

Surface condition + +Permeability under hydraulic pressure - -

Europe USA RussiaEN 934-2: additives for concrete

Various types of additives:PlasticisersSuperplasticisersWater retainerIntegral waterproofingAir entrainerSetting acceleratorHardening acceleratorSetting retarderPlasticisers and setting retardersSuperplasticisers and setting retarderPlasticisers and setting accelerators

ASTM C260: air entraining admixtures

GOST 24211-03: concrete additives. General technical requirements

ASTM C494: chemical admixtures for concrete

Classification of admixtures into 7 types:Type A: PlasticiserType B: Setting retarder Type C: Setting / hardening accelerator Type D: Plasticiser and setting retarderType E: Plasticiser and setting acceleratorType F: SuperplasticiserType G: Superplasticiser and setting retarder

3-4 – CHOICE OF TYPE OF ADDITIVE DEPENDING ON ITS PROPERTIES

3-5 – STANDARDS: MAIN NORMATIVE TEXTS RELATING TO ADDITIVES


Page E 34

Action of water

It can cause deformationShrinkage, expansion, creation of capillary

systemsIt can reduce mechanical performance

This occurs when there is too much waterIt can make the concrete frost-sensitive:

Expansion when turned to iceIt can encourage electro-chemical reactions

Carbonation, corrosion, alkali reactionIt can encourage mould and the development of

organic materialsIt can dissolve:

Gypsum, plaster, chloridesIt can transport:

Chlorides, sulphates, carbon dioxideIt can carry substances:

By gravity, by capillarity, as vapour

Consequences of excess water

An increase in the quantity of water used will have a direct effect on the levels of mechanical performance

Lowering of compressive/bending strengthLowering of compactionIncrease in porosityIncrease in permeability

And on the general quality of the concrete:Segregation Greater penetration of external agents Defects in surface finishSensitivity to evaporation, etc.

Water/cement ratioThe addition of 10 litres of water per m3 of concrete causes a loss of approximately 3 to 5 N/mm²(MPa) in the 28-day compressive strength.

4 – MIXING WATER

Mixing water is needed for the manufacture of concrete. The total mixing water is the sum of the water added to the mix and the moisture on the surface of the aggregatesThe quality of the water has an influence on the characteristics of the concrete when fresh and hardened.

The use of drinking water for mixing concrete is considered to be a safe

practice

Optimum quantity

W/C ratio

Addition of water


Page E 35

5 – CONCRETE5-1 – EN 206-1: CONCRETE – Part 1: Specification, performance, production and conformity

5-1-1 – Introduction……………………………………………………………...Page E 365-1-2 – Classification

5-1-2-1 – Exposure …………………………………………………………....Page E 375-1-2-2 – Consistence of fresh concrete…………………………………..Page E 405-1-2-3 – Compressive strength of hardened concrete ………………..Page E 405-1-2-4 – Chloride content ………………………………………………..…Page E 415-1-2-5 – Maximum size of aggregates…………………………………….Page E 415-1-2-6- Density ……………………………………………………………….Page E 41

5-1-3 – Definition of concretes for placing an order5-1-3-1 – BPS: Designed Concretes………………………………………..Page E 425-1-3-2 – BCP: Prescribed Concretes ………………………………….….Page E 425-1-3-3 – BCPN: Standardised Prescribed Concretes…..Page E 42

5-1-4 – Recommendations for the limits of concrete composition …....Page E 435-1-5 – French specifications .....…………………………………………......Page E 445-1-6 – British specifications .....…………………………………………......Page E 45

5-2 – SPECIFICATION OF FRESH CONCRETE IN USA…………………………….….Page E 48

5-3 – RUSSIA: MAIN NORMATIVE TEXTS RELATING TO CONCRETE ……………Page E 49


Page E 36

CONCRETES CONCERNED: ALL STRUCTURAL CONCRETESAll structural concretes, whether ready-mixed, mixed on site by the user of the concrete or mixes intended for the prefabrication of concrete products.The standard applies also to dense concretes and to certain lightweight concretes.

CONCRETES OUTSIDE THE FIELD OF APPLICATION: THOSE THAT ARE NOT STRUCTURAL• Concrete in trenches• Infill concrete• Packing concrete• Concrete blindings• Aerated concrete• Foam concrete• No-fines concrete• Refractory concrete• Concrete with non-mineral aggregate• Very lightweight concrete (Density <800 kg/m3)

Definition of concretes for placing an order:

Usual case BPS: Designed Concretes → BPS concretes are products that are mainly offered by ready-mixed

concrete companiesParticular case

(concrete formulated by the contractor)

BCP: Prescribed Concretes

→ BCP concretes must be formulated by a competent specifier and are products made mainly on site.

Rare case(concrete with a mix proportion

made by a tradesman)

BCPN: Standardised Prescribed Concretes

OBLIGATORY CHARACTERISTICS FOR DESIGNING A

CONCRETE

Exposure class

Strength class

Consistence class

Chloride class

Max. size of aggregates

Example of descriptionXC1 C25/30 S3 Cl 0.40 22.4

XC1

C25/30

S3

Cl 0.40

22.4

Exposure class

Compression strength class on a cylinder/cube

Consistence class of the fresh concrete

Chloride class

Maximum size of the aggregates

5-1 – EN 206-1: CONCRETE – Part 1: Specification, performance, production and conformity

5-1-1 – Introduction


Page E 37

Exposure class Description of the environment Concretes concerned: examples for information purposes to illustrate the choice of

exposure classes

X0 No risk of corrosion or attack: Non-reinforced concrete or reinforced concrete in a very dry environment.

XC Corrosion caused by carbonation: Concrete containing reinforcement or cast-in metal parts, exposed to air and moisture.

XC1 Permanently dry or wet RC inside "dry" building or concrete permanently submerged.

XC2 Humidity, rarely dry Foundations, surface of concrete in contact with water for a long time.

XC3 Moderate humidity RC inside "wet" building, external concrete sheltered from rain.

XC4 Alternately wet and drying Surface in contact with water but not coming under XC2.

XD Corrosion caused by chlorides, of an origin other than marine

XD1 Moderate humidity Surface of concrete exposed to chlorides transported through the air.

XD2 Humidity, rarely dry Swimming pools; RC exposed to industrial water containing chlorides.

XD3 Alternately wet and drying Bridge elements exposed to chloride sprays; roadways; car park floor slabs

XS Corrosion caused by the chlorides present in seawater

XS1 Exposed to air carrying marine salt, but not in direct contact with sea water Structures on or near a coast.

XS2 Permanently submerged Elements of marine structures.

XS3 Inter-tidal zone, zone subject to splashing or spray Elements of marine structures.

XF Freeze/thaw attack, with or without de-icing chemicals

XF1 Moderate saturation with water without de-icing chemicals Concrete exposed to rain and to minor/moderate frost without de-icing.

XF2 Moderate saturation with water with de-icing chemicals Concrete exposed to rain and to minor/moderate frost with de-icing.

XF3 Heavy saturation with water without de-icing chemicals Concrete exposed to rain and to severe frost, without de-icing chemicals, except for particular specifications for saturation with water (horizontal surfaces for example).

XF4 Heavy saturation with water with de-icing chemicals Concrete exposed to rain and to severe frost, with de-icing chemicals, except for particular specifications for saturation with water (horizontal surfaces for example).

XA Chemical attack: Concrete exposed to the chemical attacks produced in natural soils, surface and/or underground water.

XA1 Environment with low chemical corrosivenessRefer to the standard in Table 2 giving the limit values for the classes of exposure corresponding to chemical attack from soils and from underground water.XA2 Environment of moderate chemical corrosiveness

XA3 Environment with high chemical corrosiveness

5-1-2-1 – Exposure classes 5-1-2 – Classification


Page E 38

5-1-2-1 – Exposure classes (contd.)Residential or office buildingExt or int walls

protected from moisture

Parking, soil non protected

Internal ground slabs & slab

underground wall, foundation, piles if protected

from moistureIf corrosive soil

Road or access road

Boundary wallIf exposed to marine

atmosphere

Ext . walls unprotected from

moisture

Protected pool

If unprotected from chlorinated

water

Columns, beams, lintels

If protected from moisture

CLASS X0 No risk of corrosion / attackIn buildings, concrete is rarely used with this class of exposure

Lightly reinforced with re bars cover of 5 cm and provided there is no corrosiveness

CLASS XA1 to XA3 Environment subject to chemical corrosiveness

XA1 low chemical corrosivenessXA2 moderate chemical corrosivenessXA3 high chemical corrosiveness

Industrial environment

Agricultural environment

NB: an investigation is required in a corrosive environment to determine the level of chemical corrosiveness


Page E 39

5-1-2-1 – Exposure classes (contd.)

Class XC1, XC2

XC1, XC2 (F)Shallow foundation

XC1Int /Ext walls

protected from moisture

Reinforced concrete, risk of corrosion by

carbonation

XC1Solid slab

XD2 / XD3Water + non marine chlorideXD2 damp rarely dryXD3 alternately damp / drying

uncovered concrete

Class XS1 to XS3XS1 in contact with marine air but not with sea water (less than 1km from sea shore)XS2 permanent immersionXS3 inter-tidal zone, spray

Inter-tidal zone, spray

If less than 1km from shore

Contact with or proximity to marine salts

Class XF1 to XF4XF1slight or moderate frost without de-icing chemicalsXF2 slight or moderate frost with de-icing chemicalsXF3 severe frost without de-icing chemicalsXF4 severe frost with de-icing chemicals

Attacks due to freeze/thaw cycles on wet concrete

Depending on climatic zone




Page E 40

The standard defines 5 categories of consistence of concretes with a typical water content.

The measurement of the slump is made using an Abrams cone.

The consistence may also be checked by:• The Vebe time (in seconds): 5 Vebe categories (V0 to V5);• The degree of compactability: 4 categories of compactability (C0 to C3);• The flow table diameter (in mm): 6 categories of flow (F1 to F6).

Description

C X/Y whereC = ConcreteX = Minimum typical compressive strength (in MPa) on 150 x 300 mm cylindersY = Minimum typical compressive strength (in MPa) on 150 mm cubesExamples: C 25/30 → normal or dense concretes; LC 25/28 → lightweight concretes

Typical strength Fractile (Gauss's law): 5%, i.e. 95% of the population of all the results of the measurements of the strength of the concrete being considered are greater than the typical strength value.

Consistence class of concretes

Class S1 S2 S3 S4 S5

Slump (in mm)

10 to 40

50 to 90

100 to 150

160 to 210 ≥220

normal or dense concretes

C 8/10 C 12/15 C 16/20 C 20/25 C 25/30 C 30/37 C 35/45 C 40/50

C 45/55 C 50/60 C 55/67 C 60/75 C 70/85 C 80/95 C 90/105 C 100/115

lightweight concretes

LC 8/9 LC 12/13 LC 16/18 LC 20/22 LC 25/28 LC 30/33 LC 35/38 LC 40/44

LC 45/50 LC 50/55 LC 55/60 LC 60/66 LC 70/77 LC 80/88

5-1-2-2 – Consistence of fresh concrete

5-1-2-3 – Compressive strength of fresh concrete

Figure A shows a low slump and figure B shows a higher slump(firm) (plastic) (very plastic) (fluid) (fluid)


Page E 41

Density (in kg/m3)

Lightweight concrete from 800 to 2000

Concrete of normal density from 2000 to 2600

Dense concrete ≥ 2600

Lightweight concretes are classified in six ranges of density.

The categories of chlorides enable the composition of the concrete to be adapted according to the risk of corrosion of the reinforcement.

Standard EN 206-1 defines the maximum content of chloride ions in the concrete not to be exceeded, according to its type of use.

Use of the concrete Chloride class

Maximum content (in

Cl-)

Concrete not containing steel reinforcement or cast-in metal parts Cl 1.0 1,00%

Concrete containing steel reinforcement or cast-in metal parts

Cl 0.20 0,20%

Cl 0.40 0,40%

Concrete containing steel pre-stressing reinforcement

Cl 0.10 0,10%

Cl 0.20 0,20%

The classification of the concrete depends on the maximum size of the aggregate: nominal size greater than the largest aggregate used in the concrete (Dmax).

5-1-2-4 – Chloride content

5-1-2-5 – Maximum size of aggregates

5-1-2-6 – Density


Page E 42

Concrete for which the required properties and additional characteristics are specified to the producer by the purchaser.The producer is responsible for providing a concrete that meets these requirements.

Example of description:

This description may also include the type and the class of the cement, if they are specified.

Concrete for which the composition and the components to be used are specified to the producer by the purchaser. The producer is responsible for providing a concrete that meets this composition. The specifier's responsibility is to carry out a formulation study and to establish the detailed composition of the concrete, which he must give to the producer.The minimum information for defining a BCP is:-The reference to standard EN 206-1- The proportion of cement- The type and the strength class of the cement- The W:C ratio or the consistence of the concrete- The maximum nominal size of the aggregate and its maximum chloride content- If applicable, the type quantity and origin of the additives and admixtures.

Concrete of which the composition is defined in a standard applicable to the place of use of the concrete. The specifier is responsible, in this case, for selecting the appropriate composition for the construction from the standard.

XC1C30/37 S2 Cl 0.4022.4BPS EN206-1

Type of concrete

Compliance with the standard

Compression strength classExposure class

Maximum size of the aggregates

Consistence class

Chloride content class

5-1-3-1 – BPS: Designed Concretes

5-1-3 – Definition of concretes for placing an order

5-1-3-2 – BCP: Prescribed Concretes

5-1-3-3 – BCPN: Standardised Prescribed Concretes


Page E 43

Exposure classes

No risk of corrosion or attack

Corrosion caused by carbonationCorrosion caused by chlorides

Freeze/thaw attack Chemically corrosive environmentsSeawater Chlorides other than

seawater

X0 XC1 XC2 XC3 XC4 XS1 XS2 XS3 XD1 XD2 XD3 XF1 XF2 XF3 XF4 XA1 XA2 XA3

Max. water:cement ratio

– 0,65 0 ,60 0,55 0,50 0,50 0,45 0,45 0,55 0,55 0,45 0,55 0,55 0,50 0,45 0,55 0,50 0,45

Min. strength class C 12/15 C 20/25 C 25/30 C 30/37 C 30/37 C 30/37 C 35/45 C 35/45 C 30/37 C 30/37 C 35/45 C 30/37 C 25/30 C 30/37 C 30/37 C 30/37 C 30/37 C 35/45

Min. cement content (kg/m3) – 260 280 280 300 300 320 340 300 300 320 300 300 320 340 300 320 360

Min. air content (%) – – – – – – – – – – – – 4* 4* 4* – – –

Other requirements

Aggregates complying with prEN 12620 with sufficient freeze/thaw

strengthSulphate-

resistant cement*: If the concrete does not contain deliberately entrapped air, the performance of the concrete must be measured in accordance with an appropriate test method, in

comparison with a concrete for which the freeze/thaw strength for the corresponding exposure class has been determined.

Direction in which to read the table

5-1-4 – Recommendations for the limits of concrete composition

The values in the above table are based on the assumption of an anticipated structure lifespan of 50 years.The values are those for cement type CEM I and for aggregates of a maximum size between 20 and 32 mm.


Page E 44

The following table gives the limit values, applicable in France, of the composition and of the properties of concretes

Direction in which to read the table

Allowance for admixtures as a substitution for

cement is only permitted, within the limits of the

ratio A:A+C, with CEM I cements of class 42.5 or

52.5.

No risk of corrosion or

attack

Corrosion caused by carbonation

Corrosion caused by chloridesFreeze/thaw attack

(refer to the map giving zones of frost in the standard)

Chemically corrosive environments

Seawater Chlorides other than seawater

X0 XC1 XC2 XC3 XC4 XS1 XS2 XS3 XD1 XD2 XD3 XF1 XF2 XF3 XF4 XA1 XA2 XA3

Ratio Eeff/binder eq* max – 0,65

Num

erical values identical to XC

1

Num

erical values identical to XF1

Num


Num

erical values identical to XS

2

0,55 0,50

Num


0,55 0,50 0,60 0,55 0,55 0,45 0,55 0,50 0,45

Minimum strength class – C20/25 C30/37 C35/45 C30/37 C35/45 C25/30 C25/30 C30/37 C30/37 C30/37 C35/45 C40/50

Min. binder eq. content (kg/m3) when

Dmax= 20 mm150 260* 330 350 330 350 280* 300 315 340 330 350 385

Min. air content (%) – – – – – – – 4** 4** 4** – – –

Max. ratio

A:(A

+C)

Fly ash 0,30 0,30 0,15 0,15 0,15 0,15 0,30 0,30 0,30 0,15* 0,30* 0,30* 0,00Silica fume 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10 0,10

Ground slag 0,30 0,30 0,15 0,15 0,15 0,15 0,30 0,30 0,30 0,15 0,30* 0,30* 0,00Limestone addition 0,25 0,25 0,05 0,05 0,05 0,05 0,25 0,25 0,25 0,05 0,00 0,00 0,00

Silica addition 0,20 0,20 0,15 0,15 0,15 0,15 0,20 0,20 0,20 0,15 0,00 0,00 0,00

Nature of the cement – – PM* PM* – – – – – ** ** ** **

•*Eeff= Effective water = total water – water absorbed by the aggregatesBinder eq = binder equivalent = Cement + k Additions (k depends on the type of cement and of the addition)•**refer to the annotations in FR EN 206-1 Table NA.F.1

frost-proof aggregateCheck that the

concrete is suitable for the expected levels of

performance

5-1-5 – French specifications


Page E 45

In the United Kingdom, standard BS EN 206-1 is supplemented by BS 8500: Complementary British Standard to BS EN 206-1.

In this supplement, there is an additional way to define a concrete in an order:designed concrete (symbolised by RC, PAV, FND, GEN) for which the composition and the requirements are defined precisely in BS 8500 and which only applies to a concrete not exposed to exposure classes XS, XC and/or XA.



Page E 46

Exposure class

Blended cement

strength class, max w:c, min. cement (kg/m3), equivalent nominal cover

15 + Δc 20 + Δc 25 + Δc 30 + Δc 35 + Δc 40 + Δc 45 + Δc 50 + Δc

X0 All

XC1 All C20/25; 0.70; 240 or RC25 <<<< <<<< <<<< <<<< <<<< <<<< <<<<

XC2 All – – C25/30; 0.65; 260 or RC30 <<<< <<<< <<<< <<<< <<<<

XC3All except IVB – C40/50; 0.45;

340 or RC50C32/40; 0.55; 300 or RC40

C28/35; 0.60; 280 or RC35

C25/30; 0.65; 260 or RC30 <<<< <<<< <<<<

XC4

XD1 All – – C40/50; 0.45; 360

C32/40; 0.55; 320

C28/35; 0.60; 300 <<<< <<<< <<<<

XD2

I, IIA, IIIB-S, SRPC – – – – – C28/35; 0.55;

320 <<<< <<<<

IIIB-V, IIIA – – – – – C25/30; 0.55; 320 <<<< <<<<

IIIB, IVB – – – – – C20/25; 0.55; 320 <<<< <<<<

XD3

I, IIA, IIIB-S, SRPC – – – – – C45/55; 0.35;

380C40/50; 0.40;

380C35/45; 0.45;

360

IIIB-V, IIIA – – – – – C35/45; 0.40; 380

C32/40; 0.45; 360

C28/35; 0.50; 340

IIIB, IVB – – – – – C32/40; 0.40; 380

C28/35; 0.45; 360

C25/30; 0.50; 340

XS1

I, IIA, IIIB-S, SRPC – – – – – C35/45; 0.50;

340 <<<< <<<<

IIIB-V, IIIA – – – – – C32/40; 0.50; 340 <<<< <<<<

IIIB, IVB – – – – – C25/30; 0.55; 320 <<<< <<<<

XS2

I, IIA, IIIB-S, SRPC – – – – – C28/35; 0.55;

320 <<<< <<<<

IIIB-V, IIIA – – – – – C25/30; 0.55; 320 <<<< <<<<

IIIB, IVB – – – – – C20/25; 0.55; 320 <<<< <<<<

XS3

I, IIA, IIIB-S, SRPC – – – – – – C45/55; 0.35;

380C40/50; 0.40;

380

IIIB-V, IIIA – – – – – C35/45; 0.40; 380

C32/40; 0.45; 360

C28/35; 0.50; 340

IIIB, IVB – – – – – C32/40; 0.40; 380

C28/35; 0.45; 360

C25/30; 0.50; 340

Exposure class

Types of

cement

Strength class, max. W:C, min.

cement

Comments and other requirements

XF1 AllC28/35; 0.6; 280

XF2 All

Restriction to non-reinforced concrete

C32/40; 0.6; 300C25/30; 0.6; 280 Min. air content: 3.5%

XF3All

except IVB

C25/30; 0.6; 280

Use of freeze/thaw-resistant aggregatesMin. air content: 3.5%

C40/50, 0.45, 340

Use of freeze/thaw-resistant aggregates

XF4All

except IVB

C28/35, 0.55, 300

Use of freeze/thaw-resistant aggregatesMin. air content: 3.5%

C40/50, 0.45, 340

Use of freeze/thaw-resistant aggregates

Direction in

which to read

the table

The following table gives the limit values, applicable in the

United Kingdom, of the composition and of the properties of concretes

Δc is the margin of tolerance of the nominal minimum cover (generally in

the order of 5 to 15 mm)

Key:<<<<: do not reduce the quality of the concrete below the value indicated in

the left-hand cell



Page E 47

Sulphate and magnesium

Sulphate class

water/soil extract

underground water

Total sulphate charge pH Strength

classCombinations of

cement typesMax. W:C

Min. quantity of cement

(kg/m3)

Type of particular

aggregatesOption designated concrete

SO4g/l

Mgg/l

SO4g/l

Mgg/l

SO4%

<1,2 <0,4 <0,24 DS-1>5.5

C 8/10 All – 180 – GEN1 for non-reinforced foundations

C 25/30 All 0.65 260 – RC30 with cover 25+Δc

≤5.5 C 28/35 All except II-L or LL 0.55 300 – FND2z with cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4)

1.2 to 2.3 0.4 to 1.4 0.24 to 0.6 DS-2>5.5

C 28/35 I, IIA except II-L or LL, IIB-S, IIB-V, IIIA 0.50 340 –

FND2 with cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4)

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.55 300 –

≤5.5 C 28/35 All except II-L or LL 0.50 340 – FND3z with cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4)

2.4 to 3.7 1.5 to 3.0 0.7 to 1.2 DS-3

>5.5

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.40 400 B FND4 with cover: 25+Δc (XC2) or 30+Δc (XC3

and XC4) OR

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.45 380 C FND3 with cover: 25+Δc (XC2) or 30+Δc (XC3

and XC4) OR

C 28/35 IIB-V+SR, IVB+SR 0.35 400 AFND4 with 1 Additional Protection Measure* and cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4) ORFND3 with 2 Additional Protection Measures* and

cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4)

C 28/35 IIIB+SR, SRPC 0.40 400 A

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.45 380 B or C

≤5.5

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.40 400 C FND4 with cover: 25+Δc (XC2) or 30+Δc (XC3

and XC4) OR

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.40 400 B FND4 with 1 Additional Protection Measure* and

cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4) OR

C 28/35 IIB-V+SR, IVB+SR 0.35 400 AFND4 with 2 Additional Protection Measures* and

cover: 25+Δc (XC2) or 30+Δc (XC3 and XC4)C 28/35 IIIB+SR, SRPC 0.40 400 A

C 28/35 IIB-V+SR, IVB+SR, IIIB+SR, SRPC 0.45 380 B or C

3.8 to 6.7 ≤1,2 3.1 to 6.0 ≤1,0 1.3 to 2.4 DS-4

Refer to BS 8500-13.8 to 6.7 >1,2 3.1 to 6.0 >1,0 1.3 to 2.4 DS-4m

>6,7 ≤1,2 >6,0 ≤1,0 >2,4 DS-5

>6,7 >1,2 >6,0 >1,0 >2,4 DS-5m

A: aggregates with high carbonate content; B: aggregates with moderate carbonate content; C: aggregates with low carbonate contentAdditional Protection Measure: see BS 8500

Direction in which to read

the table

Chemical attack:BS 8500 has the particular feature of dealing with exposure class XA differently. The table summarises the chemical attacks by natural soils in the majority of cases. For particular cases, refer to BS 8500.



Page E 48

5-2 – SPECIFICATION OF FRESH CONCRETE IN USA

Standard ASTM C94 (Standard specification for Ready Mixed Concrete) describes 3 ways of ordering and specifying concrete:

Option (1) Normal: When the client requires the supplier of the concrete to be responsible for the concrete mix. The Owner shall specify the types of materials to be used, the exposure to which the concrete will be subjected, the compressive strength required for structural purposes, the maximum size of the coarse aggregate, the air content, the admixtures and any other desired property, such as slump and minimum bending strength. The supplier shall certify that the factory, the plant and the materials used meet the requirements of the standard, that the mix proportion will produce a concrete of the quality and quantity specified and that the strengths, when they are evaluated, meet the requirements of the standard.

Option (2) Prescription: When the client is responsible for the mix proportions and for the properties of the concrete.The client shall specify, per cubic metre of concrete, the types and the quantities of materials to be used, the maximum nominal size of the aggregate, the proportions by weight of the coarse and of the fine aggregates, and the maximum mass of water. In addition, the client shall specify the air content, the type of admixture and the slump at the point of delivery. The supplier shall certify that the factory, the plant and all the materials used comply with the requirements of the standard.

Option (3) Performance: When the client requires the supplier of the concrete to be responsible for the concrete "as delivered".The client shall specify the class of concrete that will meet the conditions of exposure and the architectural, structural and durability criteria. The supplier shall certify that his quality control guarantees the performance criteria (measured and noted) and that the concrete will meet the specified performance criteria prior to delivery.


Page E 49

GOST 7473: Ready-mixed concrete - Specifications

GOST 25192: Concrete. Classification and technical requirements

GOST 25246: Concrete. Chemical resistant. Specifications

GOST 25820: Lightweight aggregates concrete. Specifications

GOST 26633: Heavyweight and sand concrete. Specifications

GOST 27006: Concrete. Rules for mix proportions

GOST 25246: Concrete Chemical resistant Specifications

GOST 25881: Chemical resistant concrete. Methods of test

5-3 – RUSSIA: MAIN NORMATIVE TEXTS RELATING TO CONCRETE


Page E 50

6 – CHECKS ON CONCRETE: MAIN NORMATIVE TEXTS

Europe USA RUSSIA

Standard EN 206-1ASTM C39: Compressive

strength of cylindrical concrete specimens

GOST 10180: Concrete Method for strength

determination using reference specimens

Notation

C X/Y

f'c

compressive strength on 150 x 300 cylindrical

samples (in psi)

1000 psi = 6.89 MPa

Samples crushed at 28 days

X: compressive strength on 150 x 300 mm cylindrical samples (fc,cyl in MPa)

Test on 150 x 150 mm cuboid samples


Y: compressive strength on 150 mm cuboid samples (fc,cube in MPa)


Particularspecifications

France United Kingdomuse of fc,cyl from EN

206-1, but with 160 x 320 mm cylindrical samples

(Compliance due to the tolerance of 10% on the nominal dimensions of the 150 x 300 cylinders → no correction factors)

use of fc,cube from EN 206-1 (dimensions: 150

x 150 mm)

TYPICAL COMPRESSIVE STRENGTH


Page E 51

Main normative texts on tests of fresh concreteFrance Great Britain

NF EN 12350: Test on fresh concrete

Part 1: SamplingPart 2: Slump testPart 3: Vebe testPart 4: Degree of compactabilityPart 5: Flow table testPart 6: Determination of the density of fresh concrete Part 7: Determination of the air content - Pressure methods

BS EN 12350: Testing fresh concrete

BS 1881-125: Testing concrete - Part 125: Method for mixing and sampling fresh concrete in the laboratory

BS 1881-128: Testing concrete - Part 128: Method for analysis of fresh concrete

BS 1881-129: Testing concrete - Part 129: Method for determination of density of partially compacted semi-dry fresh concrete

Main normative texts on tests of hardened concreteFrance Great Britain

NF EN 12390: Testing hardened concrete

Part 1: Shape, dimensions and other requirements for specimens and moulds Part 2: Making and curing specimens for strength tests Part 3: Compressive strength of test specimens Part 4: Compressive strength - Specification for testing machines Part 5: Flexural strength of test specimens Part 6: Tensile splitting strength of test specimens Part 7: Density of hardened concrete Part 8: Depth of penetration of water under pressure

BS EN 12390: Testing hardened concreteBS 1881-112: Testing concrete - Part 112: Methods of accelerated curing of test cubesBS 1881-113: Testing concrete - Part 113: Methods for making and curing no-fines test

cubes

BS 1881-119: Testing concrete - Part 119: Method for determination of compressive strength using portions of beams broken in flexure

BS 1881-121: Testing concrete - Part 121: Method for determination of static modulus of elasticity in compression

BS 1881-122: Testing concrete - Part 122: Method for determination of water absorption

BS 1881-124: Testing concrete - Part 124: Method for analysis of hardened concrete

BS 1881-127: Testing concrete - Part 127: Method for verifying the performance of a concrete cube compression machine using the comparative cube test

BS 1881-130: Testing concrete - Part 130: Method for temperature matched curing of concrete specimens

BS 1881-131: Testing concrete - Part 131: Method for testing cement in a reference concrete

6 – CHECKS ON CONCRETE: MAIN NORMATIVE TEXTS (Contd.)


Page E 52

United States: Fresh concreteSampling of

fresh concreteASTM C172: Standard practice for Sampling Freshly

Mixed Concrete

Consistence ASTM C143: Standard Test Method for Slump of Hydraulic Cement Concrete

Density and yield

ASTM C138: Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of

Concrete

ASTM C231: Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method

ASTM C173: Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method

Strength sampling

ASTM C31: Standard Practice for Making and Curing Concrete Test Specimens in the Field

ASTM C192: Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory

Setting time ASTM C403: Standard Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance

Accelerated curing method

ASTM C684: Standard Test Method for Making, Accelerated Curing, and Testing Concrete

Compression Test SpecimensBleeding of

concreteASTM C232: Standard Test Method for Bleeding of

Concrete

United States: Hardened concreteStrength test on

hardened concreteASTM C39: Standard Test Method for Compressive Strength of

Cylindrical Concrete Specimens

Air contentASTM C457: Standard Test Method for Microscopical Determination of

Parameters of the Air Void Content and Parameters of the Air Void System in Hardened Concrete

Density, absorption, voids

ASTM C642: Standard Test Method for Density, Absorption, and Voids in Hardened Concrete

Portland cement content

ASTM C1084: Standard Test Method for Portland Cement Content of Hardened Hydraulic Cement Concrete

Chloride content

ASTM C1218: Standard Test Method for Water Soluble Chloride in Mortar and Concrete

ASTM C1152: Standard Test Method for Acid Soluble Chloride in Mortar and Concrete

ASTM C1500: Standard Test Method for Water Extractable Chloride in Aggregate

Petrographic analysis ASTM C856: Petrographic examination of hardened concrete

Changes in volume and length

ASTM C157: Standard Test Method for Length Change of Hardened Hydraulic Cement, Mortar and Concrete

ASTM C512: Standard Test Method for Creep of Concrete in Compression

ASTM C469: Standard Test Method for Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression

ASTM C215: Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens

Permeability

ASTM C1202: Standard Test Method for Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration

ASTM C642: Standard Test Method for Density, Absorption, and Voids in Hardened Concrete

Sulphate-resistance ASTM C1012: Standard Test Method for Length Change of Hydraulic Cement Mortars Exposed to a Sulphate Solution

Corrosion resistance ASTM C876: Standard Test Method for Half Cell Potentials of Uncoated Reinforcing Steel in Concrete

Carbonation ASTM C856: Petrographic examination of hardened concrete



Page E 53

RussiaGOST 25192: Concrete. Classification and general technical requirementsGOST 10180: Concrete. Method for strength determination using reference specimensGOST 10181: Concrete mixtures. Methods of testGOST 12730.0: Concrete. General requirements for methods of determination of density, porosity, moisture content, water absorption and water lightnessGOST 12730.1: Concrete. Method for determination of densityGOST 12730.2: Concrete. Method for the determination of moisture contentGOST 12730.3: Concrete. Method for the determination of water absorptionGOST 12730.4: Concrete. Method for the determination of porosity parametersGOST 12730.5: Concrete. Method for the determination of water lightnessGOST 22783: Concrete. Method of accelerated determination of compressive strengthGOST 24452: Concrete. Methods of prismatic compressive strength, modulus of elasticity and Poisson's ratio determinationGOST 24544: Concrete. Methods of shrinkage and creep flow determinationGOST 24545: Method of fatigue tests



Page E 54

Contractor Website Activity Presence

Lafarge www.lafarge.frCement

AggregatesConcrete

75 countries

Cemex www.cemex.comCement

AggregatesConcrete

More than 50 countries

Holcim www.holcim.comCement

AggregatesConcrete

More than 70 countries

Italcementi Group www.italcementigroup.com

CementAggregatesConcrete

19 countries

Heidelberg Cement www.heidelbergcement.com Cement

Concrete 50 countries

Fosroc www.fosroc.com Admixtures More than 20 countries

Sika www.sika.com Admixtures More than 60 countries

Degussa www.degussa.com Admixtures More than 50 countries

Chryso www.chryso-online.com Admixtures 16 countries

Grace Construction

Productswww.graceconstruction.com Admixtures

Additives

APPENDIX – MAIN WORLDWIDE MATERIALS SUPPLIERS


Page F 1

PART F: PROCESS

1 – DETERMINATION OF DAILY REQUIREMENTS……………………………Page F 2

2 – DETERMINATION OF THE CAPACITY OF THE MIXING PLANT ……Page F 3

3 – SURROUNDINGS OF THE CONSTRUCTION ……………………………Page F 4

4 – MIXING PLANT ON SITE / READY-MIX DELIVERY: SELECTION CRITERIA ………………………………………………………………………Page F 5

APPENDIX: DIAGRAM OF A READY-MIX PLANT…………………………...Page F 6


Page F 2

1 – DETERMINATION OF DAILY REQUIREMENTS

Site programme (use the period in the programme when concreting is the busiest)

Determination of the average daily quantity of concrete to be produced: Q

Determination of the peak (maximum daily quantity of concrete to be produced): Qmax

Q max = Q x 1.30

For indicative purposes, concreting on typical building sites runs in cycles. The organisation of the cycles will depend on the size of the site. An estimate of approximately 3 to 4 hours per day on average of concreting can be used (generally placed at the end of the day).Particular case: Floor slabs in industrial buildings, which can be placed continuously throughout the day.

Large civil engineering sites, which require a longer period for the preparation of formwork and of reinforcement, as the units to be constructed are generally larger.

Determination of the hourly quantity of concrete to be produced: Q time spent placing = Q max / dFor indicative purposes, Q time to be calculated > ~ 80 m3/hr → Large quantity

Q time to be calculated < ~40 m3/hr → Small quantity

Determination of the time taken each day for concreting: d (in hours)

See note below


Page F 3

2 – DETERMINATION OF THE CAPACITY OF THE MIXING PLANT

Practical site output = Theoretical supplier output / 1.20 Theoretical supplier output = Q time for placing x 1.20

Why 1.20?The supplier's theoretical output takes into account a theoretical minimum mixing time. In reality, this time will be longer on site.

Case 1: Approach based on an existing plant (its theoretical output is known) Case 2: Approach based on site requirements

OR

Q time for placing ≤ Practical site output?

YESIn this case, the plant is capable of supplying the

site with concrete

NOIn this case, the capacity of the plant is insufficient. A

different or additional plant must be selected

A plant must be selected that has a theoretical production output that is not less than that calculated above.


Page F 4

3 – SURROUNDINGS OF THE CONSTRUCTION

Supply of components (cements, aggregates, etc.)Are supplies of components regular in this country?For indicative purposes, developed and developing countries generally do have regular supplies.It should be noted that Africa and Russia have irregular supplies

NOAllow for a stock for approximately 7 to 10 days, or even more

under exceptional conditions, and for the necessary space

YESAllow for a stock for approximately 3 days and for the necessary space

Site locationIs the site located in a country and in a location to which read-mixed concrete can be delivered? For indicative purposes, ready-mix plants are rare in Africa.

Space available on the siteHow much on-site space is available?Is there enough space to set up a mixing plant?In order to measure the space needed to set up a mixing plant on site, allowance must be made:- for the size of the plant (which will depend on the daily quantity of concrete to be produced)- for the space needed to store the components

NO

YESCarry out a comparative

study of the cost of setting up a mixing plant on site /

ready-mix deliveries. See next page

NOLook for space to rent close to

the site

YESInstallation of a mixing

plant on site


Page F 5

4 – MIXING PLANT ON SITE / READY-MIX DELIVERY: SELECTION CRITERIA

If there is enough space on site to set up a mixing plant:

Comparative study of the cost of ready-mix / plant on site

Ready-mix is less expensive

Ready-mix is more expensive

Choose the location for a mixing plant on site Check the quality of the concrete

Check that the mixing plant is capable of supplying the site by visiting itRecommendations when inspecting the ready-mix plant:

- Look at the reliability of the installations (appearance of the equipment and maintenance)- Ask for test graphs and analyses- Find out about the types of concrete that can be produced, their strength ranges, etc.- Find out about the origin of the cements and the types used- Find out about the origin of the aggregates, their treatments, their storage (under shelter / exposed to bad weather), etc. (if importation necessary, estimate the costs)- Check the reliability of production and of supplies (transport)

In general, if the site is located in a country

with an active concrete industry, ready-mix will be more competitive

Conditions generally favourable for setting up a plant on site:-Large quantities of concrete to be placed-Enough space available-The market of suppliers of concrete components independent from that of ready-mixed concrete

The mixing plant is not reliableChoose to set up a mixing plant

on site

The mixing plant is reliableChoose ready-mixed concrete deliveries

With effect from the instruction to start work, it will take about 3 to 5 months for the installation of the plant


Page F 6

APPENDIX: DIAGRAM OF A READY-MIX PLANT

A delivery of aggregatesB aggregate reception hopperC aggregate storageD conveyor beltE storage of cementitious materialsF hopper scalesG delivery of cementH mixer

I admixturesI mixer lorry with excess concreteK recycled waterL recovered aggregatesM pumpN water storageO loading into a mixer lorryP control room


Page G 1

Part G: PLACING AND SPECIAL CONCRETES1 – GENERAL PLACING OF CONCRETE

1-1 – FORMWORK………………………………………………………………………..Page G 21-2 – TRANSPORT…………………………………………………………….……. ….Page G 41-3 – VIBRATION OF THE CONCRETE………………….…………………….… ….Page G 51-4 – CURING OF THE CONCRETE………………..……………………………….…Page G 81-5 – STRIKING FORMWORK……………………………………………………….....Page G 101-6 – DAY JOINTS IN CONCRETE……………………………………………............Page G 11

2 – SPECIAL CONCRETES2-1 – COMPACT AND ONLY SLIGHTLY PERMEABLE CONCRETE ………….Page G 122-2 – BHP: HIGH-PERFORMANCE CONCRETES…………………………….…..Page G 132-3 – BAP: SELF-PLACING CONCRETES………………………………………….Page G 152-4 – FIBRE CONCRETES……………………………………………………………..Page G 182-5 – CONCRETE FOR FACEWORK ………………………………………..……...Page G 192-6 – LIGHTWEIGHT CONCRETES AND DENSE CONCRETES……………...…Page G 222-7 – PUMPED CONCRETES…………………………………………………………Page G 232-8 – OTHER SPECIAL CONCRETES…………………………………..…………..Page G 24

3 – ARCHITECTURAL DESIGN………………………………………............….....Page G 25

4 – PARTICULAR APPLICATIONS4-1 – COMPLEX SHAPES AND HIGH DENSITIES OF REINFORCEMENT… ..Page G 264-2 – CONCRETING OF LARGE CONSTRUCTIONS………………………. .....Page G 274-3 – CONCRETING IN HOT WEATHER……………………………………. …...Page G 284-4 – CONCRETING IN COLD WEATHER……………………………………. …...Page G 29


Page G 2

Suitable for constructions of complex, non-repetitive shapes

Possible use to imitate timber facings

Use planks that are sufficiently thick (27 to 40 mm) made from species of timber free from tannin, dry and stabilised to prevent any warping

Modification of the characteristics of the timber as it is reused (lower porosity, surface wear) → influence on the surface colour and appearance

Speed of installation and assembly Possibility of reuse for units of a repetitive nature

(vertical walls, suspended floors)Encourage the dispersal of the heat caused by the

hydration of the cement → favourable criterion in hot weather

Smooth surface of the concreteVery suitable for external vibration if the design of the

formwork permits

Concrete less well protected against drops in temperature in cold weather (→ lagging of the formwork if necessary)

The main types of formwork

Timberformwork

Metalformwork

Formwork provides as its main functions:- moulding of the shape- moulding of the surface texture- maintaining stability until hardening- protection against drying out during setting and hardening

1 – GENERAL PLACING OF CONCRETE

1-1 – FORMWORK

Main componentsWhatever the nature of the formwork, there are always the same components:- A skin former which determines the final appearance (shape and texture) of the moulded item- A framework which limits deformation of the skin former (thrust of fresh concrete, self-weight of the concrete, etc.)- Spacer rods, struts for stability, props to enable the position of the formwork surfaces to be adjusted- Units built into the formwork or independent, to enable workers to work perfectly safely

bad


Page G 3

Recommendations

Check that the formwork is clean, and properly oiled or waxed

Before fixing the reinforcement, check that the mould oil specified is suitable for the conditions of temperature and for the quality of surface finish and that it has been applied uniformly and without excess

Inserts, holes and pre-frames:•Before closing, check the setting out and the quality of the holding devices•Check that the pre-frames can be withdrawn without difficulty•Check compliance with the proper rules for spacing between services cast into the concrete (electricity, heating, etc.)

Tightening rods•Before tightening, check that they are suitable for the pressure of the concrete (diameter and quantity)

Setting out and watertightness•Check the setting out and the verticality of the formwork, the correct tightening of the rods and the watertightness of the formwork

Stability•Carefully check the stability of the formwork

1-1 – FORMWORK (contd.)


Page G 4

1-2 – TRANSPORT

Recommendations to be followed during transport

The equipment used to transport the concrete must be cleaned frequently with water, in order not to introduce foreign bodies or rubbish into the concrete

The equipment must be such that the height that the concrete drops, as it is being placed, or the mechanical impacts as it is being handled, are not such as to create problems of segregation in the concrete

The time taken to transport the concrete must be limited, depending on the ambient temperature, humidity and wind conditions.For indicative purposes, in France, it must not exceed 1½ hours, as far as transport of ready-mixed concrete in a rotary mixer lorry is concerned. Concrete produced on site must be placed within 30 mins of production

In hot weather (T> 25°C), the use of retarded concrete is recommended, in order to prevent setting starting before placing is complete.

The concrete must be placed before it starts to set, otherwise it will lose strength and, in addition, there is a risk of extra water being added by the site in the mixer in order to restore its initial consistency, with all the risks that that includes. Setting may be more or less rapid, depending on the type of cement, the water content, the temperature of the fresh concrete and the type of additive.

The addition of water on delivery must not be permitted, due to the harmful effect of such additions on the strength of the concrete.For indicative purposes, the addition of 20 litres of water per m3 of concrete type C25/30 makes its strength drop by 5 MPa.


Page G 5

Usual general rules:Internal vibration

Rapidly submerge the vibrator into the heart of the mass of concrete and raise it slowly and regularly.

Never bring the vibrator into direct contact either with the reinforcement (risk of segregation), or with the formwork (risk of segregation, bubbling, staining, etc.).

Never use the vibrator to reposition the concrete (risk of segregation).

The choice of vibrator will depend on its capacity (depending on the nature of the concrete) and its diameter (depending on the size of the construction and the density of reinforcement).

Stop vibration as soon as:The concrete is no longer settlingAir bubbles are no longer being released (excess vibration may

lead to recycling of the air, leading to further bubbles and possibly segregation).Laitance begins to appear on the surface; this becomes shiny.The noise emitted by the vibrator stabilises.

Choice of vibrating head:Diameter of action (in cm) = diameter of the vibrator (in mm)E.g.: vibrator Ø = 50 mm → action Ø = ~50 cm

Objective of vibration

Vibration = high-quality concretePlacing made easierImproved strengthDurable concrete

More attractive facework

Vibration equipment:

Equipment providing internal vibration of the concrete (or pervibration): the vibrator acts directly in

the concrete

Equipment providing external vibration: the vibrator acts on the concrete via the formwork, which is

specifically designed.

1-3 – VIBRATION OF THE CONCRETE

de-aerating the concrete… …compacting it…

…filling the mould


Page G 6

Vibration of horizontal units: Suspended slabs, ground slabs, rafts

Do not slope the vibrator by more than 45°

Do not drag the head horizontally

Gaps between immersion points for the vibrator(s) identical to those for the vibration of vertical units.

Vibration of vertical units

External wall or cross wallVibration in layers 50 to 60 cm high of concretePenetration of the head into the layer immediately below by about 10 cmSpacing (e) between 2 points of vibration: e ~ 1.7 x radius of action of the vibrator

In situ concrete

Window in central opening:Vibration in layers of 50 cm on one side only (1) until concrete appears on the other side (2), and checking that the section underneath has been filled (3).

Opening for door or blank opening:

Columns and piersApplication of the above criteria, especially the thicknesses of the layers and day joints for a thickness of 10 to 15 cm into the layer below

If the reinforcement is too close together, provide a shaft of a suitable size for the passage of the vibrator, or consider external vibration.

1-3 – VIBRATION OF THE CONCRETE (contd.)

formworkformwork

Dia too large


Page G 7

Usual general rules:External vibration

May be usefully advised when the construction has tightly-packed reinforcement or very dry concrete, or if automationon the site is well developed.

Position the centre line of the vibrator perpendicularly to the strutsupporting the fixing system

Set the direction of rotation of the vibrator towards the formwork

Harmonise the vibrations of all the vibrators (speed of rotation, frequency, centrifugal force)

With external vibration, the compaction of the concrete is more homogenous than with internal vibration. Period of vibration andlaboriousness are reduced.

1-3 – VIBRATION OF THE CONCRETE (contd.)

Reminder In order to avoid the need to vibrate the

concrete, self-placing concrete, for example, should be used


Page G 8

Objectives of curingCuring enables the concrete to retain the water used in its composition so as to:

Obtain the specified compressive strength Improve durabilityEnsure the routine maintenance and finish of the concrete

The water will evaporate faster as the temperature increases,

as ambient humidity drops and as the wind

increases.(see figure opposite)

DANGER

1-4 – CURING OF THE CONCRETE

Example: Air temperature = 22°CConcrete temperature = 36°CRelative humidity = 90%Wind speed 5 kph → D=0.6 kg/m²/hr → OK22 kph → D=1.8 kg/m²/hr → Danger

Risks in the absence of curing•Open cracks (increased shrinkage)•Reduction in surface strength•Increase in the porosity of the surface concrete•Reduction in durability (corrosion of reinforcement, frost resistance, etc.)

A-Continual treatment against moistureB-In air after 28 days of wet curingC- n air after 7 days of curingD-Continually in air

A

B

C

D

Relative humidity (%)

Evaluation of levels of evaporation of moisture from the surface of concrete covered with water

Wind speed (km/h)

Concrete temperature (°C)

Air temperature (°C)

Leve

l of e

vapo

ratio

n (k

g (m

2/h)

)1- starting from air temperature, find the graph of relative humidity 2- move to the right up to concrete temperature3- move down to wind speed4- move to the left to read approx. level of evaporation


Page G 9

Methods of curingUse of non-permeable formwork

Limit the time the formwork is needed to avoid cracking by restrained shrinkage Use of watertight forms

Not to be used in the case of unfinished faceworkApplication of curing products

To be sprayed onto the fresh concrete to prevent the mixing water from evaporatingPreferably use approved products and check compatibility with the mould oil and subsequent finishesNo curing product on day joints

Curing by humidification:This can be carried out by:•Working in a saturated atmosphere•Use of mats, canvas, etc., kept wet by intermittent watering

Period of curing

It must be continuous and homogenous.The curing must be continued until the concretehas reached a strength of approximately 0.5 fc28

For indicative purposes, the table opposite is extracted from ENV 13670: Execution of concrete structures. It indicates the minimum curing periods for the classes of exposure in EN 206 apart from X0 and XC1

1-4 – CURING OF THE CONCRETE (contd.)

Surface temperature of the concrete

(t) in °C

Minimum curing period, days a) b)

Development of the strength of the concrete d)

r = fcm2 / fcm28

rapidr ≥ 0.50

mediumr = 0.30

slowr = 0.15

very slowr < 0.15

t ≥ 25 1,0 r 2,0 3,025 > t ≥ 15 1,0 2,0 3,0 5,015 > t ≥ 10 2,0 4,0 7,0 10,010 > t ≥ 5 c) 3,0 6,0 10,0 15,0

a) Add any setting time in excess of 5 hrsb) Linear interpolation between the values of the rows is permittedc) For temperatures lower than 5°C, the period of time for which the temperature is lower than 5°C must be addedd) The development of the strength of the concrete is the ratio of the strength at 2 days to the average strength after 28 days, determined by prior tests or based on the experience of concrete of a comparable composition


Page G 10

1-5 – STRIKING FORMWORK

For indicative purposes, in France, except in the case of the use of sliding forms or thermal treatments, striking is not carried out until the compressive strength of the concrete has reached a sufficient value of at least 5 MPa.

In average weather conditions (ambient temperature of 10° to 25°C, relative humidity greater than 60%), it can be estimated that this strength is reached 12 to 14 hrs after the end of placing.

This value will depend, in particular, on the nature of the cement, the amount used and on the shape of the construction.

Recommendations

Cold weather = slowing of hardening = keeping formwork and props for longer

Remove the formwork and the props progressively, without impact, without damaging the concrete, when the strength of the concrete is sufficient

Avoid overloading a floor slab locally during and after the striking of formwork; otherwise take it into account in the determination of the minimum strength

If there is a need for uniformity of colour for the facework, strike at constant maturity(same length of time and same actual strength on striking)

If the formwork forms an element of the curing system, the time prior to striking must be taken into account

The formwork and its props must not be dismantled until the concrete has achieved sufficient strength:•In order to withstand damage to the surface as the formwork is struck•In order to support the loads it has to carry at this stage•In order to avoid deflection that exceeds the specified tolerances


Page G 11

A "Day Joint" is formed where fresh concrete is poured in contact with old concrete, in order to ensure aesthetic or mechanical continuity between the two concretes.

Recommendations

General recommendations:The surface of the old concrete must be clean: dust, laitance, curing products and any mould release agents must be removed

by blowing with compressed air and/or with water under pressure The surface of the old concrete must not be covered with standing waterThe reinforcement must be stripped clean and correctly positionedThe vibration of the fresh concrete poured close to the surface of the old concrete must be carried out particularly

carefully

Precaution in hot weather: the surface of the old concrete must be protected from exposure to the sun and must be dampened regularly

Fresh concrete in a thin layer: The old concrete must be dampened particularly at the contact with the fresh concrete and particularly careful curing must be carried out after the new concrete is poured.

Day joint on a vertical or steeply sloping surface: the support must be cleaned in order to remove all traces of mould release agent. The support is generally prepared by blasting the surface with water under pressure or by blowing with air plus water. The roughness of the contact surface is given by the formwork for the concrete in the first phase.

Day joint on a horizontal surface. The support may be prepared by:- blowing with air plus water onto the fresh concrete just after setting begins- blasting the surface of the old concrete with water under pressure- sand blasting or blasting the old sound concrete with water at very high pressure

1-6 – DAY JOINTS


Page G 12

2 – The various types of CONCRETES

2-1 – COMPACT AND ONLY SLIGHTLY PERMEABLE CONCRETE

General definition

Suitable formulation Adequate cement content, sufficiently high (see example opposite)

•Low water content: use of additives (superplasticisers which enable large reductions of water content while maintaining excellent behaviour when placed, without reducing the plasticity and consistence of the mix)

•Particle size including a sufficient quantity of fine elements to fill the gaps between the larger aggregates. The increase in the extent of the granular skeleton by the use of ultrafine particles (silica fume, microfiller, limestone, etc.) will enable the compactness of the concrete to be increased even more

→ Low W/C ratio (<0.6)

Careful placing•Suitable and homogenous vibration (Page G 5)

•Effective curing to avoid excessive drying out of the concrete at a young age (Page G 8)

•Monitor temperature and humidity during placing and on the following days

Suitable design of the construction (Page G 25)

Avoid creating zones where water accumulates and stands and where surface water will create run-off channels

Example with a high quality C25/30

Sufficient quantity of fines Q (<80µm) ≥ 350 kg/m3 including at least 250

kg/m3 of CEM1Q (<160µm) ≥ 400 kg/m3Q (<315µm) ≥ 520 kg/m3

Fluid consistence (S4)Limited quantity of water (CEM 1 + additions E/Léq ≤

0.55 to 0.60) Reminder: Leq = binder equivalent = Cement + k Additions

(k depends on the type of cement and of the addition)Mixing continued for approximately 1 min after adding the

final ingredientClean and watertight formworkCorrect cover to reinforcementRelease agent (previously tested and a minimum quantity)No further water added after mixing in the mixing plantConcrete placed without a long waitDropping height limited to 1.50 mPlacing in horizontal strips approximately 40 to 60 cm highGood vibration


Page G 13

High Performance Concretes are characterised by:a 28 day compressive strength on cylinder of more than 50 MPa an Effective Water/Binder Equivalent ratio less than 0.4

CharacteristicsCompressive strength: This is a characteristic that is often used to classify HP

concretes. Gains in strength can be seen from a young age; a 60 MPa concrete at 28 days may exceed 15 MPa at 24 hours and 40 MPa at 7 days.

Creep: This is much less than that of usual concretes. The creep ratio (deferred deformation / instantaneous deformation), in the order of 2 for usual concretes, drops to between 1 and 1.5 for a 60 MPa concrete.

Class Rc at 28 days (MPa) on cyl.

Ordinary concretes 20 to 50

High performance concretes (HP) 60 to 100

Very high performance concretes (THP) 100 to 150Exceptional concretes > 150

PropertiesGood consistence of fresh concrete: these are fluid concretes with a very low W:C ratio.Good performance at young agesVery low porosityImprovement in the resistance to chemical attack (favourable behaviour in a marine

environment), to freeze/thaw phenomena and better protection of the reinforcement(reduction in the progression of carbonation)

Reduction in deformation under instantaneous and permanent loads

AdvantagesImproved durabilityOptimisation of structuresReduction of planned and reactive maintenance

costsArchitectural durability of the constructionsPossibility of accelerating construction speed

2-2 – BHP: HIGH STRENGTH CONCRETES

Racoourcissement du au fluage - Béton ordinaire

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Points at riskFire resistance: in buildings, limited resistance (C80/95), due to spalling problems at

high temperatures; otherwise need to add polypropylene fibres Shrinkage: total shrinkage of HP concrete equivalent to ordinary concrete, but

high initial endogenous shrinkage Delayed Ettringite Formation: need to limit rises in temperature in large units in a damp

environment

Shortening due to creep – Standard concrete

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Page G 14

Superplasticisers and water reducers: Enable a reduction in water content at the same consistence and increase the short-term strength of the concrete. Proportion depends on the desired W:C ratio, their effectiveness and their compatibility with the cement

Ultrafines (silica fumes): Supplement the particle size of the concrete and increase compaction and mechanical strengthAggregates: Must have:

A high strength (hard and compact material)A high G:S (gravel:sand) ratioAn irregular shape (preferably crushed) to improve paste / aggregate adhesionA D in the order of 10 to 16 mm

CementsCement with a high strength at a young ageCement quantity of between 400 and 500 kg/m3

2-2 – BHP: HIGH STRENGTH CONCRETES (contd.)

C 25/30

C100/115

C 50/60

C 150/180

ORDINARY CONCRETE →CONCRETE WITH

IMPROVEDMECHANICAL

CHARACTERISTICS

BHP HIGH PERFORMANCE

CONCRETE

BTHPVERY HIGH

PERFORMANCECONCRETE

EXCEPTIONAL CONCRETE

CementsIncrease in the quantity of cementReduction of the W:C ratio

For indicative purposes: For a C 25/30, Cement ~ 280 – 300 kg/m3; W:C ~ 0.55 – 0.60For a C 40/50, Cement ~ 380 – 390 kg/m3; W:C ~ 0.45

The aggregates must have a higher strength if the mechanical strength is to be increased

Examples of exceptional concretes: UHPFRC: Ultra High Performance Fibre Reinforced Concrete, Ductal

Components and mix proportions

Example of HP type formulation CEM I – 52.5 385 kg/ m3Silica fume 30 kg/ m3 28 day strength 87 MPaSand 0/5 690 kg/ m3 7 day strength 75 MPaGravel 4/12 220 kg/ m3 Creep factor 0,8Gravel 10/20 940 kg/m3Effective water 130 kg/m3Superplasticiser 4 to 7 kg/m3


Page G 15

Self-placing concrete is characterised by its hyperfluidity, meaning that it can be placed by gravity, without the need for vibration.

PropertiesVery fluid and pumpableAbsolutely homogenousPlacing without vibration and without impactHas similar strength and durability to those of traditional concretes and of high-performance concretes

ConsequencesProductivity improvements

Rapidity of placingImproved construction speedReduction in maintenance costs

Saving of labour Reduced placing timeLimited making good

Improvement in working and environmental conditions Difficulty of tasks Site safetyReduced noise problems

Improvement in the quality of facework

Other terms defining this concrete:Self-levelling concreteSelf-compacting concrete: SCCHyper-fluid concrete

Points at riskFormulation:

Water content must be closely controlled Continuous particle size (otherwise risk of bleeding)

Not negligible additional cost Setting delayed in cold weather (if no precautions)Increased thrust in formwork

2-3 – BAP: SELF-PLACING CONCRETES


Page G 16

Composition and production

Optimisation of the granular structure (sand and gravel) of the concrete:Continuous particle size graphsLower Dmax of aggregatesHigh fines content

Systematic use of "superplasticiser" or "water reducing" plasticiser additives

W:(C + fines or additions) ratio close to 0.35 (main quality factor of a self-placing concrete)

Increase in mixing time in comparison with a traditional concrete

Strict control of the water content of the mix (within ± 10 litres) and, consequently, of the aggregates

2-3 – BAP: SELF-PLACING CONCRETES (contd.)

Example of typical formulation CEM I – 42.5 (R) / 52.5 (R) 300 kg/m3Fly ash 180 kg/m3Sand 0/5 750 kg/m3Gravel 4/12 220 kg/m3Gravel 10/20 650 kg/m3Effective water 190 kg/m3Superplasticiser 3 to 6 kg/m328 day strength 38 / 43 MPa (depending on

cement)


Page G 17

Recommendations for placing:

Specific site preparation and organisation: self-placing concretes require a change of habits and the adaption of traditional construction methods: plant – staff – construction phasing – rigorous wedging of the reinforcement and of inserts to form holes

Use of clean, watertight and stronger formwork in order to compensate for the hydrostatic thrust on the formwork.In typical uses (walls 2.8 m high), the thrust during placing does not exceed the strength limits of the formwork. In the case of walls of great height and/or with very many openings, the formwork must be specially designed.

Falls: limit falls to 2%Use of suitable mould release products in order to avoid the phenomena of micro-bubblingCareful curing: as these concretes are more sensitive to the phenomena of shrinkage due to drying out (particularly horizontal

surfaces)

As for all concretes, it is necessary, during the concreting phases, to take the weather conditions into account and to implement particular arrangements outside the temperature range (+5°C to 35°C)

Placing with a traditional mixer and discharge pipeThe concrete is placed from the top of the formwork by means of a discharge pipe. The pipe is slid into the formwork in order tolimit the drop height. The diameter of the pipe under the mixer drum has to be adapted in comparison with traditional concrete (60 to 80 mm diameter instead of 150 to 200 mm diameter) so that it can be inserted between the reinforcement.

Placing by pumping from the bottom of the formwork: "source" pumpingThis method is suitable, in particular, for vertical units of great height. It avoids the need for working at the top of the formwork.

Placing by pumping at the top of the formwork with a plunger tube The plunger tube must be inserted far enough into the formwork to limit the dropping height as much as possible.

2-3 – BAP: SELF-PLACING CONCRETES (contd.)


Page G 18

The objective sought is to give the concrete better resistance to tensile forces and to deformation, thus enabling the construction of thin units that are more ductile and that have good wear- and impact-resistance.As opposed to traditional reinforcement, the fibres are distributed throughout the mass of the concrete and thus give rise to a material which, considered on a macroscopic scale, has a homogenous nature.

CharacteristicsThe properties may vary according to the nature of the fibres used; however, certain trends can be seen that are common to all fibre concretes

Improved tensile strength: the material develops micro-cracks as it lengthens, the role of the fibres being to delay failure by opposing the spreading of the cracks ("sewing" effect)

Encourages micro-cracking of the concrete, less detrimental and more attractive than wide cracksImprovement in the mechanical strength of the concrete

•Early strength•Impact resistance •Shear strength•Wear- and abrasion-resistance

Improvement in surface appearance for synthetic fibre and glass fibre concretesImprovement in respect of plasticity and moulding for synthetic fibre concretesImprovement in fire resistance for glass fibre concretes

Different types of fibresSynthetic fibres (acrylic, aramid, carbon, nylon,

polyester, polyethylene, polypropylene)Natural fibres (asbestos, cellulose)Metal fibresGlass fibres

2-4 – FIBRE CONCRETES

Main usesGround slabs for industrial buildings (metal or polypropylene fibres)Does away with the need for an anti-cracking welded mesh

Polypropylene fibres on the left and steel fibres on the right

Bridge deck with steel fibres

Without fiber With fiber


Page G 19

Mechanical surface treatments

Washing: This is carried out on fresh water using a water jet. The material is finely washed at very low pressure. The water removes surface laitance and enhances the aggregate. This treatment does not affect the colour of the aggregates used

Brushing: The facing is brushed (hard non-metallic brush), with or without water.

Sand blasting: This consists of attacking a hardened facing with a jet of sand projected by compressed air, in order to strip, more or less, the aggregates, which, depending on their hardness, are more or less rounded by this technique. Dark aggregates are made lighter by this treatment

Bush hammering: Once the facing has completely hardened, it is attacked with a manual or pneumatic bush hammer, with teeth or needles at variable spacings to suit the desired appearance.

Filling: Intermediate operation in the polishing and sand-blasting of the skin of the concrete after hardening, which consists of filling any small cavities that may have appeared during this surface treatment with a cement paste.

Grinding: This is a rough grinding mill, which exposes more or less all of the components of the concrete and gives a rough surface. Theground concrete is passed over once with the grinder before filling

Polishing: This is based on the use, after rough grinding, of mills with finer and finer grains, which, by eliminating the traces left by the previous mills, bring out the texture of the mass concrete and give a perfectly smooth facing.The polished concrete is given 2 or 3 passes, depending on whether the aggregate is light- or dark-coloured, before being filled. As for a marble polish, this is obtained by between 4 and 6 passes, depending on the nature of the aggregate, before being buffed and filled.

2-5 – FACEWORK CONCRETES


Page G 20

2-5– FACEWORK CONCRETES (contd.)

Colouring of the concrete

Through-colouring: The general colour of the concrete can be modified by adding pigments. Mineral pigments, the only pigments that can be used in concretes, are capable of absorbing part of the white light that they receive, by only reflecting the fraction corresponding to their colour. Some of these pigments can be found in nature, whence their name of natural pigments (e.g.: oxides of certain minerals, such as iron, chromium, titanium, cobalt, etc.).Depending on their particle size, pigments of an identical colour have different colouring powers. This must be taken into account in the quantity used.

Paint: This is a traditional means of adding colour to concrete. By hiding the background material, the paint substantially modifies its appearance.

Stains: Neither paints nor varnishes, stains for concrete are acrylic polymers in solution, which colour the concrete and enhance it without concealing it. Stains protect the concrete from water – while allowing dirt to wash off – and from attack by carbon dioxide and sulphates.

Chemical surface treatments

Deactivation: This is based on the use of a setting retarder deactivator, applied to the formwork before the concrete is placed, which delays its setting on the surface. The skin of the concrete may also be removed by washing with a jet of water, followed by brushing.

Acid etching: This consists of attacking the facing of hardened concrete with a solution based on hydrochloric acid. The depth of the attack varies according to the concentration of the solution and the length of time of the treatment. This must be followed by washing with a large quantity of water in order to avoid the depassivation of the concrete and the corrosion of the reinforcement. It is used only on siliceous aggregates


Page G 21

2-5– FACEWORK CONCRETES (contd.)

Washed beige Washed ochre Washed blue Washed green Washed grey Washed black

bush-hammered beige bush-hammered ochre bush hammered blue bush hammered green bush hammered grey bush hammered black

sand-blasted beige sand-blasted ochre sand-blasted blue sand-blasted green sand-blasted grey sand-blasted black

polished beige polished ochre polished blue polished green polished grey polished black


Page G 22

The attraction of lightweight concretes lies in the large saving that can be made in the self-weight of the construction. Lightweight concretes have densities of between 300 and 1800 kg/m3, against 2300 kg/m3 for a traditional concrete. This quality is also sought for thermally insulating concretes, their conductivity varying in the same way as their density. They alsohave better fire resistance.

These concretes are obtained:Either by the use of lightweight aggregates (clay or shale or

expanded glass or pumice)Or by the creation of a multitude of millimetric micro-bubbles

(foam or cellular concrete)Or by the use of very lightweight micro-beads (perlite,

vermiculite, expanded polystyrene)Or by the production of a no-fines concrete (porous concrete)

These concretes are twice as likely to shrink or creep

On the other hand, the use of very dense aggregates (barite, magnetite) enables the production of concretes of a density in excess of 3000 kg/m3.These concretes are used for protection against radiation or to construct abutments, counterweights (where the dead weight of the concrete is an overriding requirement), etc.

LIGHTWEIGHT CONCRETES DENSE CONCRETES

2-6 – LIGHTWEIGHT AND DENSE CONCRETES


Page G 23

2-7 – PUMPED CONCRETES

Concrete transported by pipework and not in a lorry. This process for delivering concrete is pushed through tubes from a supply hopper to the location of placing. It enables horizontal distances of up to 400 m (or even 1.5 km) and vertical distances of 100 m (or even 300 m) to be covered. The typical flow rate of the pumps varies between 8 m3/hr and 70 m3/hr. It may reach 160 m3/hr on large items.

Points at risk Ensure a constant supply of fresh concrete (pump hopper always loaded, in order to maintain the homogeneity of the

concrete)Check that a constant flow rate is maintained in the supply pipes and clean the pipes at the end of each operationPumping through vertical, angled or flexible pipes considerably reduces the maximum pumping distance

AdvantagesLiberation of the craneAccess to difficult locationsTransport over great distancesContinuous supply of fresh concreteImproved construction speed

RecommendationsFormulation of the concrete

Fines content (including cement) must be in the order of:-400 to 420 kg/m3 for fines less than 0.160 mm-350 kg/m3 for fines less than 0.080 mmAggregates:

- if possible rolled- particle size as continuous as possible- the diameter of the coarsest gravels must be less than one quarter of the diameter of the pipesAdditive: : if possible, add a plasticiser to reduce W:C; add a superplasticiser for a slump greater

than 15 cmThe consistence of the concrete must be plastic: cone slump between 5 and 15 cm

PlantEquivalent transport distance = D + 5xH + 10xC1 + 5xC2 (in m) where D: horizontal distance in m,

H: difference in level in m upwards; C1: number of 90° bends; C2: number of 135° bendsProtect the pipework from the sun in hot weather (light colour, watering, etc.) or use of a setting

retarderProvide a straight length of at least 4 m at the outlet from the pumpAt the beginning of the operation, it is recommended to send "lubricating mortar" through the pipe,

which, as a general rule, is not used in the construction Floor slab: tilt the end of the pipe upwards (see photograph above)

Principle

Pumping through a flexible tube is carried out by crushing a flexible tube between rubber rollers, driven by a chain or a rotor. This system is used for pumping over short distances (length 50 m, difference in level 10 m) and for flow rates in the order of 15 m3/hr.

Piston pumps comprise two pistons working in opposition. One cylinder pushes the concrete into the tubes while the other sucks the content of the supply hopper. A distribution system using a swivelling tube ensures continuity of pumping.

Characteristics and sizing of the pump

For a given manufacturer, the choice will depend:-On the flow rate of the concrete in m3 per hour-On the diameter of the distribution pipes-On the length of the pipes and the height to be raised-On the consistence of the concrete to be used


Page G 24

2-8 – OTHER SPECIAL CONCRETES…

UNDERWATER CONCRETES

Concrete placed under water and, therefore, poured in the presence of water pressure, for which allowance must be made when carrying out the worksThe composition of this concrete must be studied very carefully, using, in particular, water-repellent colloidal agents that increase the forces of attraction between particles and, thus, the cohesion of the concrete

NO-FINES CONCRETES

Concrete obtained by the omission or very great reduction of fine aggregate: it is therefore the product of a mixture of coarse aggregates and cement paste.No-fines concrete is used particularly for insulation.

ULTRA-HIGH-PERFORMANCE FIBRE-REINFORCED CONCRETE - DUCTAL

Fibre-reinforced concrete with exceptional levels of performance (very great consistence, very high compressive strengths – 150 to 200 MPa - , very great durability).Their formulations require specific superplasticiser additives, specific aggregates, ultrafine particles and fibres.

SPRAYED CONCRETES

Concrete sprayed, after mixing either wet or dry, onto a background in the form of a jet, in successive layers. It enables the most complex shapes to be formed (domes, shells, etc.). It is also often used in underground works.

REFRACTORY CONCRETES

Concretes capable of withstanding continuous very high temperatures of up to 1600°C, whereas a traditional concrete "lets go" at 300°C. An aluminous cement with a high alumina content must be used in the formulation, together with refractory aggregates.


Page G 25

A properly adapted design of the construction will avoid the formation of zones where water can collect and stand and of locations where surface water will create run-off channels

Avoid traps where water can collect (hollows, projections, etc.)Prevent water running down the construction (drips, cornices, flashings, etc.)…

3 – ARCHITECTURAL DESIGN (a few examples)

Joinery profile to form weather

drip

Joinery or face of wall

Outside face inside face

slope


Page G 26

High density of reinforcement: ratio > 200 kg of steel per m3

Examples complex shapes, heavily-reinforced load-bearing elements (High Rise Buildings)

Traditional concretes:

Concretes that have to be vibrated so as to prevent segregation when passing through the reinforcement or in restricted spaces

Formulation of the concreteSmall particle size (Dmax < 12.5 mm)Fluid consistence of the fresh concrete (S4 or S5)High proportion of fines (Q(< 80 µm) >~ 400 kg / m3)Water-reducing additive to achieve consistence targets

PlacingLimit the dropping height and provide tipping templates suitable for the spacing

of the reinforcementFavour, if possible, placing by pumpingVibration equipment compatible with the construction (vibrating heads of a

diameter to suit the spacing of the reinforcement)Vibration time suitable for the consistence of the concreteAvoid causing the formwork and the reinforcement to vibrateParticular care to be paid to the waterproofing of the formwork

Self-placing concretes:

Particularly suitable solution for constructing very complex shapes and constructions with very high

densities of reinforcement

4 – PARTICULAR APPLICATIONS

4-1 – COMPLEX SHAPES AND HIGH DENSITIES OF REINFORCEMENT


Page G 27

Objectives:

To limit the maximum temperature of the concrete during its hardening phase (do not exceed 65 to 70°C for Portland-based cements

To limit the thermal gradient generally to 20°C, between the skin and the core of the concrete in order to avoid any danger of cracking

Recommendations

Favour cements with a low heat of hydration

Measure the heat in the core of the concrete using sensors

In summer, lower the initial temperature of the concrete by using ice in the mixing water and by watering the aggregates

Preferably use aggregates with a high Dmax in order to limit the quantity of cement

Protect the skin of the concrete (curing) from the thermal shocks that may be caused by the external environment

If the thermal gradient is well in excess of 20°C, provide the necessary reinforcement to absorb the thermal forces and to limit the danger of cracking.

Importance of the choice of cement in the construction of a raft in hot weather:For a large construction with a fresh concrete temperature on delivery = 25°C, cement content 350 kg/m3

Example 1: cement CEM I 52.5 N CE CP2 NF → Tmax = ~ 70°C (T calculated at 2 days in the core of the mass) → To be avoidedExample 2: cement CEM III/C 32.5 N CE PM ES NF → Tmax = ~ 45°C (T calculated at 2 days in the core of the mass) →OK

4-2 – CONCRETING OF LARGE CONSTRUCTIONS


Page G 28

RecommendationsRecommendations relating to formulation

Preferably use a cement with a low hydration heat and avoid a cement with rapid developmentNever add extra water in excess of the formulationAdd a plasticiser, if necessary, or a water-reducing superplasticiserAdd a setting retarder

Recommendations for production and transportProtect the water, the cement and the aggregates from the sun as much as possiblePreferably use the aggregates in the morning, after they have cooled down at night, or cool them before use by watering them (in this

case, allow for the additional water)Use cold waterIf supply is from a ready-mix plant, take steps to limit the temperature of the fresh concrete on departure, reduce transport and waiting

time and limit the time the mixer lorries spend parking in full sun.

Recommendations for concretingAdapt the times for concreting according to the temperature (coolest times of the day)Carry out placing as quickly as possibleDo not add water to try and improve the consistence of the concrete Protect the formwork (in particular metal formwork) from direct sunlight and, possibly, cool it by wetting it before concreting

Protection of the concretesProtect from evaporation immediately after placing, particularly surfaces exposed to the sun and to the wind, using a curing product,

by a tarpaulin (wet mats, polyethylene film, etc.) or by using a water spraying system.Maintain the protection for the first few hours, or even a few days, depending on how the weather changesProvide all arrangements to enable the heat to escape so as to keep the concrete at an acceptable temperature (protection from sunlight,

frequent watering of the formwork, etc.).

When young, concrete is sensitive to heat. A rise in temperature accelerates setting and hardening, causes the evaporation of the mixing

water and may therefore have an unfavourable effect on the characteristics of the hardened concrete.

As a general rule, as soon as the temperature measured on site

(temperature taken in the shade, 1.50 m above the ground) is sustainably

greater than 25°C, previously defined

particular arrangementsmust be taken for

concreting.

Above 35°C, as far as possible, concreting

should be deferred to a more favourable period.

4-3 – CONCRETING IN HOT WEATHER


Page G 29

Cold and frost may have harmful consequences on the quality and the levels of performance of the concrete

At an external temperature of 5°C:

The setting time is in the order of 10 hrs against 2.30 hrs at 20°C.

The compressive strengths at 2 days are in the order of 2 MPa against 15 to 20 MPa at 20°C

On site, the temperature must be measured regularly, as it conditions the steps to be taken. The site thermometer must be positioned 1.50 m above ground level, sheltered from rain and sun.

Below a temperature of 5°C, setting may be sufficiently affected to change the development of the hydration reaction.

The hydration kinetics stop as soon as the temperature of the concrete drops below 0°C.

The time after placing before the concrete is "frost-proof" is in the order of 3 days at a temperature of at least 5°C. A concrete subjected to frost within this time is practically irrecoverable, whereas, after that time, the cold only causes hardening to slow down.

4-4 – CONCRETING IN COLD WEATHER

Seen in a microscope, traces of frost in the paste of a fresh concrete. The ice crystals

form as the fresh concrete freezes

Time before striking formwork versus temperature Start of concrete setting versus temperature

(compressive strength in MpA)

Minimum striking time

timeStart of setting


Page G 30

Recommendations

Recommendations relating to formulationPreferably use rapid-hardening cements, with high hydration heat and high early strengthIf necessary, increase the quantity of cementReduce the quantity of water by using suitable additives: water reducers, setting accelerators,

hardening acceleratorsCarry out prior studies of cement/additive compatibility under conditions close to those of the site.

Recommendations to create and maintain a quantity of heat in the fresh concreteUse heated mixing water and maintain the temperature after placing by heating the formworkStore the aggregates in a frost-free place and, in an extreme case, possibly heat them before

adding them to the mixing plantIf possible, use formwork that has insulation (lagging)

(namely: timber formwork more insulating than metal formwork)Reduce the transport time between the concrete production plant and the site by as much as possible

and place the concrete in the formwork as quickly as possible If the water temperature > 60°C, modify the way the components are added to the mixer so that the

water is not directly in contact on its own with the cement

Maintain the protective devicesKeep the concrete warm, if possible, as it hardens, by using insulating tarpaulins and by adding heatProtect the surface of the concrete in contact with air from cold (for example: insulating tarpaulin,

insulation boards) and, more especially, units that are not very thickKeep the concrete at a minimum temperature of between 15 and 20°C (never dropping, especially,

below 5°C) during its setting and its initial hardening (use of electric heaters for example)

Recommendations for striking formworkKeep the surface protection for at least 72 hrsOnly strike the formwork if the concrete has reached sufficient minimum strength in the order of

5 MPa to 10 MPa so as to be able to withstand subsequent forces during the following phases of concreting.

An increase in the temperature of the components of the concrete may raise its temperature, for example:

An increase of 10°C of the water raises the temperature of the concrete by 2°C

An increase of 10°C of the aggregates raises the temperature of the concrete by 7°C

An increase of 10°C of the cement raises the temperature of the concrete by 1°C

4-4 – CONCRETING IN COLD WEATHER (contd.)

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