VOLUME STABLE CONCRETE USING SHRINKAGE REDUCING AND EXPANSIVE AGENTS -

APPLICATION IN STRUCTURES WITH SENSITIVE CRACKING BEHAVIOR

Kaspars KravalisProduct manager joint-less floors

New ideas in concrete

industry

Additive producers,

scientists

Contractors, end

users

Sometimes only for

lab, even perfect

Only what needed,

economical

Volume stable, shrinkage free

concrete

History of shrinkage reduced, compensated concrete

2000 years – expanding agents

50 years – expanding cements

40 years – SRA agents

15 years – combination of expanding agents and SRA

now – combination of all known + fibers = standards?

SHRINKAGE

Plastic reduced by SRA

Autogenousreduced by SRA and expanding additive

Chemical and dryingsmall reduction by SRA

Thermalcontrol with good mix design and reinforcement

Challenges before

Practically complicated

and....

PriceSRA agents historically used in dosages 2-5% from cement weight

Tasks we got from concrete industry in Scandinavia

To find best effect/cost margin for SRA agent use

To reduce thicknesses of slabs up to 20-30% due to less shrinkage

To make solution for use in joint-free slabs, bridge decks, tunnel walls, water dams, etc.

MAPEI answer to market questions and needs

Process of Mapecrete SRA-N behaviour

Shrinkage with increasing dosages of Mapecrete SRA-N

Around 40-50% shrinkage reduction using only SRA

How to get away even up to 70% of shrinkage?

Mapecrete® System - technology leans on the synergetic effect between an expansive agent (EXPANCRETE) and a shrinkage reducing admixture (MAPECRETE SRA-N)

+

Mix design

Material Dosage

Sand 0-8mm 64% of total aggregate

Stone 8-16mm 36% of total aggregate

Cement 315 kg/m3

Water 175 kg/m3

Superplasticiser (Dynamon XTend) 0,9% of cementweight

Expancrete 15 kg/m3

Mapecrete SRA-N 3,2 kg/m3

Steelfibre DE 50/0,75 N 35 kg/m3

Results – synergetic effect

ESEM

Reference concrete Mapecrete SRA-N + Expancrete

• Concrete is more dense• Less gaps between grains

Possibilities with Mapecrete system

If shrinkage is eliminated up to 50-70% and using proper slab calculation guidelines like TR34 (British):

Slabs can be reduced in thickness up to 30%

Max joint space for internal slabs – up to 50mMax for external – up to 30m

Joint free slab

Traditional slab 6*6m cut

Less concrete, less CO2 footprint

Around 400 000 m3 of concrete produced in last years all

around Scandinavia and Baltics using Mapecrete system for shrinkage reduction

Application – retail centers

COOP Bygg, Stavanger, Norway

Application – industrial floors

Warehouse Helsingborg, Sweden

Application – parking decks

Parking, Jesheim, Norway

Application – airport decks

Airport Lulea, Sweden

Application – decorative floors

Car showroom, Gislaved, Sweden

Application – bridge decks

Mosetertoppen, Hafjel, Norway

Application – special architectural concrete

Kodasema thin wall cabin houses in Estonia

Design awards in New York, London, etc.

Application – bridge pillar repair

Used also already in Lithuanian projects

• MEGA shopping center parking Kaunas

• Klaipeda sea port

• SANITEX projects

• many more

CONCLUSIONS

It is possible to reduce up to 70% from total

shrinkage

Mix designs contain around 0,7-1,5% SRA and 4-6%

expanding agents

System has been approved nicely in last years in

Scandinavian sites

Thank You for your attention!