Intro to Concrete Mix DesignNH Structural Engineers Association
American Society of Civil Engineers
September 22, 2009
Traditional Concrete Making
Materials
• Portland cement
• Coarse aggregate
• Fine aggregate
• Water
Modern Concrete Making
Materials
• Portland cement
• Coarse aggregate
• Fine aggregate
• Water
• Chemical admixtures
• SCM’s
• Other admixtures/additives
• Air entrainers, fibers,
pigments
Objective In Designing Concrete
Mixtures
To determine the most economical & practical combination
of readily available materials to produce a concrete that will
satisfy the performance requirements under particular
conditions of use
Designing Concrete MixturesFactors to be considered
• Workability
• Placement conditions
• Strength
• Durability
• Appearance
• Economy
Designing Concrete MixturesFactors to be considered
• Strength – important to the
design engineer
• Durability – important to the
owner
• Workability – important to
the contractor
• Economy – important to the
owner
Proportioning concrete is the art of optimizing
the mixture to meet these requirement
ProportioningAbsolute Volume Method
• ACI 211.1: Normal, Heavyweight & Mass
Concrete
• ACI 211.2: Lightweight Concrete
• ACI 211.3: No-Slump Concrete
• ACI 211.4R: High Strength w/Fly Ash
• ACI 211.5: Submittal of Concrete
Proportions
Absolute Volume
• Concrete mixture
proportions are usually
expressed on the basis of
the mass of ingredients
per unit volume1yd
1yd
1yd
weight
volume
Concrete is batched
by weight
Concrete is sold
by volume
Absolute Volume
Material Volume Density Mass
(yd3) (lb/ yd3) (lb)
Air 0.060
Water 0.150 1685 253
Cement 0.111 5319 590
Sand 0.245 4455 1095
Stone 0.434 4455 1937
Total 1.000 3875
Selecting Mix Characteristics
• Strength requirements
• Determine W/CM
• Coarse aggregate
requirements
• Air content
• Workability
• Water content
• Cement content
• Cement type
• Admixture effects
• Fine aggregate
requirements
• Moisture corrections
• Trial mixes
Determine Strength RequirementSpecified strength, f’c, is determine from:
• Structural design considerations
• Durability considerations (ACI 318)
• Although the durability of concrete is not directly
related to strength-strength is used as an indirect
means of assuring adequate durability
• Proper concrete construction
– Proper mix design
– Proper placement & consolidation
– Proper curing
• Moisture/Temperature/Time
Requirements of ACI 318
Building CodesMax W/CM Min. f’c
psi
Concrete intended to have low
permeability when exposed to water
0.50 4000
Concrete exposed to freezing &
thawing in a moist condition or to de-
icing chemicals
0.45 4500
Corrosion protection of reinforcement
in concrete exposed to chlorides
0.40 5000
Requirements For Sulfate
Exposure
Sulfate Exposure Max. W/CM Min. f’c
psi
Negligible ---- ----
Moderate 0.50 4000
Severe 0.45 4500
Very Severe 0.40* 5000
* - ACI 318 allows a W/CM of 0.45 & f’c= 4500 for this exposure
Determining Strength Requirement
• Probability that the average of three
consecutive tests(ave. of two cylinders) is
smaller than f’c is 1%
– f’cr = f’c + 1.34S
• Probability of an individual test being more
than 500 psi below f’c is 1%
– f’cr = f’c + 2.33S - 500
Select the higher value
Standard DeviationIf only 15 to 29 consecutive test are available-
multiply the standard deviation by the following modification
factors:
Number of Tests Modification Factor
Less than 15 ----
15 1.16
20 1.08
25 1.03
30 or more 1.00
Determine Required Water-
Cement RatioThe W/CM is determine from:
• Durability
considerations
• Required strength
Requirements of ACI 318
Building CodesMax W/CM Min. f’c
psi
Concrete intended to have low
permeability when exposed to water
0.50 4000
Concrete exposed to freezing &
thawing in a moist condition or to de-
icing chemicals
0.45 4500
Corrosion protection of reinforcement
in concrete exposed to chlorides
0.40 5000
Requirements For Sulfate
Exposure
Sulfate Exposure Max. W/CM Min. f’c
psi
Negligible ---- ----
Moderate 0.50 4000
Severe 0.45 4500
Very Severe 0.40* 5000
* - ACI 318 allows a W/CM of 0.45 & f’c= 4500 for this exposure
W/CM Required for Strength• Use data from field or trial mixes using same material
• Where no data is available use table from ACI 211
Required
Strength
f‖cr
W/CM
Non-air
W/CM
Air
7000 0.33 ----
6000 0.41 0.32
5000 0.48 0.40
4000 0.57 0.48
3000 0.68 0.59
2000 0.82 0.74
Coarse Aggregate Requirement
• Grading
• Nature of particles
– Shape
– Porosity
– Surface texture
Max Aggregate Size
• Cover between steel & form,
C: Dmax < 3/4C
• Spacing between bars, S: Dmax
< 3/4S
• Distance between forms, B:
Dmax < B/5
• Depth of slab, D: Dmax < D/3
Max Aggregate SizeFor pumped concrete
• Dmax < 1/3 diameter of
hose or 1-1/2 inch,
whichever is smaller
Fineness Modulus of Sand
• The FM is calculated from
particle size distribution of
the sand
• Values should range between
2.3 to 3.1
• Coarse sand has a higher FM
than fine sand
• FM influences the bulk
volume of coarse aggregate
Bulk Volume of Coarse Aggregate
Max Size
(in.)
-------- 2.40 2.60 2.80 3.00
3/8 0.50 0.48 0.46 0.44
½ 0.59 0.57 0.55 0.53
¾ 0.66 0.64 0.62 0.60
1 0.71 0.69 0.67 0.65
1½ 0.75 0.73 0.71 0.69
2 0.78 0.76 0.74 0.72
3 0.82 0.80 0.78 0.76
6 0.87 0.85 0.83 0.81
Bulk volume of dry-rodded coarse aggregate
per unit volume of concrete for different FM
of fine aggregate
Bulk Volume of Coarse Aggregate
• Values in table are based on aggregate in a dry-rodded condition(ASTM C-29)
• They are suitable for producing concrete with a moderate workability suitable for general concrete construction
• Less workable concrete(slip-form paving)-the bulk volume can be increased by10%
• For more workable concrete(pumping)-the bulk volume can be decreased by 10%
Air ContentThe amount needed depends on:
• Max aggregate size
– Less paste as size
increases
• Level of exposure
Effect of air content on water demand:
Rule of thumb-
Decrease water by 5lb/yd for each 1% air
Workability Requirements
• Concrete must always be
made with a workability,
consistency and plasticity
suitable for job
placement
Workability Requirements
Workability Requirements
Concrete Construction Slump
Max
Slump
Min
Reinforced walls & footings 3 1
Plain footings, caissons, and
Substructure walls
3 1
Beams & reinforced walls 4 1
Columns 4 1
Pavements and slabs 3 1
Mass concrete 3 1
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
•Water demand
•Cement content
•Paste content
•Cost
•Shrinkage
•Heat evolution
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater demand is influenced by:
• Slump requirement
• Aggregate size
• Aggregate shape
• Air content
• Cementing materials content
• Temp
• Admixtures
– Water-reducing
– Mid & High range
Water ContentWater requirement for Non-Air-Entrained
concrete:
Slump
Inches 3/8 1/2 3/4 1 1-1/2 2 3
1 to 2 350 335 315 300 275 260 220
3 to 4 385 365 340 325 300 285 245
6 to 7 410 385 360 340 315 300 270
Nominal Max Aggregate Size(inches)
Same chart for Air-Entrained concrete
Water Content
• Values shown are for
angular crushed stone.
These estimates can be
reduced approximately:
• 20 lbs for sub-angular
• 35 lbs for gravel with
some crushed particles
• 45 lbs for rounded gravel
Water ContentEffects of admixtures
• Virtually all structural concrete is placed with a water-reducing admixture
• Typical effects
– Normal:5-10% reduction
– Mid:5-18% reduction
– High:12-30% reduction
• Adjusting slump
– Increase/decrease by add/delete 10lb/yd of water
Cement ContentCement Material Content= Water Content
W/CM• Minimum cement content may be
specified for the purpose of:
– Durability
– Finishability
– Wear resistance
– Appearance
• Excessively high cementitious contents should be avoided for:
– Economy
– Avoid adverse effects
• Workability
• Shrinkage
• Heat of hydration
Cement ContentGeneral recommendations(PCA):
• Cementitious material > 564lb/yd³ for severe
freeze-thaw, deicer, and sulfate exposures
• Cementitious material > 650lb/yd³ for
concrete to be placed under water(also
W/CM < 0.45)
Cement ContentGeneral recommendations(PCA):
• For workability, finishability, and durability
in flatwork cementitious material to follow
recommendations in table:
Max Aggregate
(inches)
Min Cement
(lbs)
1-1/2 470
1 520
3/4 540
1/2 590
3/8 610
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Aggregate Retained Chart
8 -18
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
% of total that is retained on 3/8 in. sieve and largerCoarseness Factor 100
% of total that is retained on the #8 sieve and larger
11.7% 25.0% 12.5% 10011.7% 25.0% 12.5% 7.1% 5.0%
49.2% 100
61.3%
80.3
Coarseness Factor
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Workability Factor3
3
3
3
3
3
565 lb/ydWorkability Factor % of total that passes the #8 sieve 2.5
94 lb/yd
623 565 lb/yd 38.6% 2.5
94 lb/yd
58 lb/yd 38.6% 2.5
94 lb/yd
40.1
cm
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Admixture EffectsThe use of admixtures may affect the water & air
content as follows:
• Water reducers typically decrease water by 5 to
10% and may increase air contents by up to 1%
• HRWR decrease water between 12 to 30% and
may increase air contents by up to 1%
• Calcium chloride-based admixtures reduce water
by about 3% and increase air by up to 0.5%
• Retarders may increase air contents
• Fibers will increase water demand
Cement Content
• Quality depends mainly on w/cm & the water contentshould be held to a minimum to reduce cement content by using:
– Largest practical max aggregate size
– Optimum aggregate gradation
– Optimum ratio of fine to coarse aggregate
– Water-reducing & air-entraining admixtures
– SCM’s(fly ash & slag)
Cement Type
– Type I – Normal
– Type II – Some sulfate resistance
low heat
– Type III – High early strength
– Type IV – Low heat of hydration
– Type V – High sulfate resistance
05 US production- 93 million tons from 113 plants in 37 states
Cement Type
Sulfate
Exposure
Cement
Type
Negligible No special type required
ModerateII,MS,IP(MS),IS(MS),P(MS),
I(PM)(MS),I(SM)(MS)
Severe V(HS)
Very Severe V(HS)
Cement TypeThe use of fly ash, slag or blended cements should
be considered in conjunction with Portland cement
wherever possible for the purpose of:
• Improving economy
• Improving workability
• Reducing heat of hydration
• Increase long-term
strength
• Improve durability
– Reduced permeability
• Freeze/thaw & corrosion
– ASR
– Sulfate resistance
Fly Ash, Slag, Silica Fume,
and Natural Pozzolans
Also known as —
Supplementary Cementing Materials (SCMs)
— a material that, when used in conjunction
with Portland cement, contributes to the
properties of the hardened concrete through
hydraulic or pozzolanic activity, or both.
Supplementary Cementitious
Materials (SCMs)
From left to right:
• Fly ash (Class C)
• Metakaolin (calcined clay)
• Silica fume
• Fly ash (Class F)
• Slag
• Calcined shale
Why Use SCM’s
• Lower heat of hydration
• Improved workability(silica fume???)
• ASR resistance
• Higher strength
• Lower permeability
• Better concrete at lower cost
Alkali-Silica Reaction
Why Do SCM’s Work in
Concrete• Have the same basic
minerals as in portland cement
– CaO
– SiO2
– Al2O3
• Different proportions than Portland cement
• Possibly different mineral phases
Secondary Cementitious
Materials
• Cementitious Materials
– Fly Ash
– Ground Slag
– Silica Fume
• Chemically react with cement and water to make more―glue‖
• Lower early strength,higher later strength
• Better quality concrete
Secondary Cementitious
MaterialsCautions
• Less controlled than cement
• Composition depends on
origin
• Can change the properties of
the concrete(setting, water
demand,admixture behavior)
Cement Hydration Process
Cement + Water CSH + CaOH
Cement Hydration Process
Cement + Water CSH + CaOH
SCMs + CaOH more CSH
Secondary Cementitious
Materials• Fly ash
– By-product of coal burning industry
– Finer than cement – round shape
• Easier to pump
• Reduces the amount of mixing water
• Fly ash bleeds less, improves finishing
• Sets slower – lower heat of hydration
• Less expensive than Portland cement
Secondary Cementitious
Materials
• Fly ash
– Does not lose slump as rapidly
– May be harder to entrain air
– Chemical composition varies
– Flowable fill market
Specifications and Classes of Fly Ash
• Class F—Fly ash with pozzolanic properties
• Class C—Fly ash with pozzolanic and cementitious properties
ASTM C 618 (AASHTO M 295)
Fly Ash
SEM Micrograph of
Fly Ash Particles
Secondary Cementitious
Materials• Ground Slag
– By-product of the
iron making process
– Produces strong and
durable concrete
– Sets slower
– Lower early
strength but much
higher 28 day
strengths
Specifications and Grade of Ground
Granulated Iron Blast-Furnace Slags
• Grade 80
Slags with a low activity index
• Grade 100
Slags with a moderate activity index
• Grade 120
Slags with a high activity index
ASTM C 989 (AASHTO M 302)
SEM Micrograph of
Slag Particles
Secondary Cementitious
Materials• Silica Fume
– By-product of electric furnaces in silicon metal
production
– 100 times smaller than a cement particle
– Used in structures
where durability is
important
– Very low addition rate
10% by weight of
cement or less
– Expensive – limited
supply
Specification for Silica Fume
ASTM C 1240
Silica Fume—finely divided residue
resulting from the production of
silicon, ferro-silicon, or other
silicon-containing alloys that is
carried from the burning surface area
of an electric-arc furnace by exhaust
gases.
SEM Micrograph of
Silica Fume Particles
Typical Amounts of SCM
in Concrete by Mass of
Cementing Materials• Fly ash
– Class C 15% to 40%
– Class F 15% to 25%
• Slag 20% to 70%
• Silica fume 5% to 10%
• Calcined clay 15% to 35%
– Metakaolin 10%
• Calcined shale 15% to 35%
Effects of SCMs on Freshly Mixed Concrete
Water requirements
Workability
Bleeding & segregation
Air content
Heat of hydration
Setting time
Finishability
Pumpability
Plastic shrinkage cracking
Fly ash SlagSilica
Fume
Reduced no/little effect
Increase varies
Effects of SCMs on Hardened Concrete
Strength gain
Abrasion resistance
Freeze thaw/scaling resistance
Drying shrinkage
Permability
Alkali silica reactivity
Chemical resistance
Carbonation
Concrete color
Fly ash SlagSilica
Fume
Reduced no/little effect
Increase varies
Effect On Reducing ASRASTM C 441
• Type F Ash:
– 15% replacement: 47%
– 25% replacement: 66%
– 35% replacement: 81%
• Type C Ash:
– 15% replacement: 3%
– 25% replacement: 14%
– 35% replacement: 20%
Concrete can play a major role in
attaining LEED certification
LEED version 2.1
Materials & Resource category
•Credit 4-Recycled Content: up to 2 points for using building
products that incorporate recycled content materials
•Masonry products are ideal candidates for incorporating recycled
materials because of the inert nature
•SCMs such as fly ash, slag cement, silica fume are considered
post-industrial material
•Glass, slag, recycled concrete masonry, or other recycled materials
as aggregate are considered post-consumer material
LEED version 2.1
Materials & Resource category
•Credit 5-Local/Regional Materials: up to 2 points for using
building products that incorporate materials produced locally.
•Selecting materials & products from local manufacturers to a job
site supports the regional economy.In addition, selecting local
vendors minimizes fuel & handling cost for shipping products
•1 point earned for using a minimum of 20% of building materials
produced regionally within a radius of 500 miles
•Additional 1 point added if 50% of building materials produced
regionally within a radius of 500 miles
Cement TypeThe use of fly ash or slag impact the mix proportions
in a number of ways including:
• Changes in water demand
– Fly ash reduces
– Slag has minimal effect
– Silica fume increases
• Changes in volume due to different
specific gravities(Portland cement =
3.15)
– Fly ash = 1.9 to 2.8
– Slag = 2.85 to 2.95
– Silica fume = 2.25
• Changes relationship between w/cm
& strength
Cement TypeACI 318 Building Code also places limits on the
maximum amount of SCM allowed in concrete
exposed to de-icing salts as follows:
• Slag < 50%
• Fly ash < 25%
• Silica fume < 10%
• Total SCM in concrete
with slag < 50%
• Total SCM in concrete
without slag < 35%
Fine Aggregate Requirements
• Convert to volumetric proportions using appropriate material density
• Calculate the volume of sand required to make up a unit volume(1yd³)
• Convert volume of sand to mass quantity using appropriate density
Mass Proportions(lb/yd³)
• Cement content
• Water content
• Coarse aggregate
Already determined
Moisture Corrections
• Mix proportions are calculated in a SSD state
• But corrections to free water in both fine & coarse aggregate are needed to maintain proper design volume
• Total free water from aggregates is than subtracted from total batch water
• Most ready mix facilities now have moisture probes and moisture adjustments are done continuously
Trial Mixes
• Trial batches are performed to determine whether the slump, air content and strength are as required
• If not, modifications to the mix are made and further trials are performed until all properties are met
Absolute Volume ExampleConditions & Specifications
• Concrete pavement
• 8 inches thick
• Exposed to moisture
& deicer salts in
severe freeze-thaw
environments
• Slump 0f 3 in. +/- 1 in.
• No statistical data
Absolute Volume ExampleConditions & Specifications
• Fine aggregate
– Natural sand
– S.G. = 2.64(SSD)
– Fineness modulus, FM
= 2.70
– Absorption, abs. =
0.9%
– Moisture content, mc =
3.5%
• Coarse aggregate
– Well graded gravel w/ some crushed particles
– 1 in. nominal max size
– S.G. = 2.68(SSD)
– Dry-rodded bulk density = 2700lb/yd³
(100lb/ft³)
– Absorption, abs. = 0.5%
– Moisture content, mc = 2.0%
Absolute Volume ExampleConditions & Specifications
• Admixtures
– Water-reducer:
• 7% water reduction at 5.5 fl. Oz. Per 100 lb of cement
• S.G. +/-= 1.0
– Air-entraining admixture
• Manufacturer recommends 1.0 fl. Oz. Per 100 lb of cement for
6% air
• S. G. +/-= 1.0
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
From this information a trial mixture is
proportioned to meet the conditions and
specifications
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Specified strength for design = 3500 psi
Note requirements of ACI 318 Building Code
Max
W/CM
Min. f’c
psi
Concrete intended to have low
permeability when exposed to
water
0.50 4000
Concrete exposed to freezing &
thawing in a moist condition or
to de-icing chemicals
0.45 4500
Corrosion protection of
reinforcement in concrete
exposed to chlorides
0.40 5000
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Specified strength for design = 3500 psi
Note requirements of ACI 318 Building Code
F’c = 4500 psi
Since less than 15 consecutive test are available
Specified Strength
F’c (psi)
Required Average
Strength F’cr (psi)
Less than 3000 F’c + 1000
3000 to 5000 F’c + 1200
Over 5000 1.10 F’c + 700
F’cr = 4500 + 1200 = 5700 psi
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
W/CM required for strength
Required
Strength
f‖cr
W/CM
Non-air
W/CM
Air
7000 0.33 ----
6000 0.41 0.32
5000 0.48 0.40
4000 0.57 0.48
3000 0.68 0.59
2000 0.82 0.74
5700 0.34
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
W/CM required for durability
Note requirements of ACI 318 Building Code
Max
W/CM
Min. f’c
psi
Concrete intended to have low
permeability when exposed to
water
0.50 4000
Concrete exposed to freezing &
thawing in a moist condition or
to de-icing chemicals
0.45 4500
Corrosion protection of
reinforcement in concrete
exposed to chlorides
0.40 5000
W/CM = 0.34 is to be used
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Bulk Volume of Coarse Aggregate
Max Size
(in.)
-------- 2.40 2.60 2.80 3.00
3/8 0.50 0.48 0.46 0.44
½ 0.59 0.57 0.55 0.53
¾ 0.66 0.64 0.62 0.60
1 0.71 0.69 0.67 0.65
1½ 0.75 0.73 0.71 0.69
2 0.78 0.76 0.74 0.72
3 0.82 0.80 0.78 0.76
6 0.87 0.85 0.83 0.81
Bulk volume of dry-rodded coarse aggregate
per unit volume of concrete for different FM
of fine aggregate
0.68
2.70
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Mass of Coarse Aggregate
Oven dry mass = bulk volume X bulk density
Oven dry mass = 0.68 X 1650 = 1836 lbs
Coarse Aggregate Content(SSD) = 1845 lbs
absorption
Mass in SSD = 1836 X 1.005
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Specified Air Contents (tolerance +/- 1.5%)
Exposure
-------- 3/8 1/2 3/4 1 1-1/2 2 3
Mild 4.5 4.0 3.5 3.0 2.5 2.0 1.5
Moderate 6.0 5.5 5.0 4.5 4.5 4.0 3.5
Severe 7.5 7.0 6.0 6.0 5.5 5.0 4.5
Nominal Maximum Aggregate Size(in.)
Air required = 6.0% +/- 1.5%
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Slump specified at 3 in. +/- 1 in.
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Water Requirements(lbs/yd³) for air-entrained concrete
Slump
Inches 3/8 1/2 3/4 1 1-1/2 2 3
1 to 2 305 295 280 270 250 240 205
3 to 4 340 325 305 295 275 265 225
6 to 7 365 345 325 310 290 280 260
Nominal Max Aggregate Size(inches)
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Water Requirements(lbs/yd³) for air-entrained concrete
295 - 35 = 260
260 - 18 = 242
(from table) (for rounded gravel
with some crushed
particles)
(7% reduction for water
Reducing admixture)
Water content = 242 lb/yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Cement Content Requirements
Cement content = Water content
W/CM
Cement content = 242
0.34
Cement content = 712 lb/yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Cement Type Requirement
No special requirements
Type I (ASTM C 150)
Use either
Type GU (ASTM C 1157)
Note: if SCM are used ensure that proportions do
Not exceed limits of ACI 318 Building Codes for
Concrete exposed to deicer salts
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Admixture Requirements
Water-reducer dose
Air-entrainment dose
5.5 fl. oz. / 100 lb X 712 lb/yd³ = 39.0 fl. oz./yd³
1.0 fl. oz. / 100 lb X 712 lb/yd³ = 7.0 fl. oz./yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Material
Mass
(yd³)
Density
(lb/ yd³)
Volume
(yd³)
Cement 712 5308
Water 242
Stone
(SSD) 1845
Air
6% by
volume
Total
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Material
Mass
(yd³)
Density
(lb/ yd³)
Volume
(yd³)
Cement 712 5308
712
5308
Water 242
Stone
(SSD) 1845
Air
6% by
volume
Total
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Material
Mass
(yd³)
Density
(lb/ yd³)
Volume
(yd³)
Cement 712 5308
712
5308 0.134
Water 242
Stone
(SSD) 1845
Air
6% by
volume
Total
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Material
Mass
(yd³)
Density
(lb/ yd³)
Volume
(yd³)
Cement 712 5308
712
5308 0.134
Water 242 1685
242
1685 0.143
Stone
(SSD) 1845 4516
1845
4516 0.409
Air
6% by
volume
6
100 0.060
Total
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Material
Mass
(yd³)
Density
(lb/ yd³)
Volume
(yd³)
Cement 712 5308
712
5308 0.134
Water 242 1685
242
1685 0.143
Stone
(SSD) 1845 4516
1845
4516 0.409
Air
6% by
volume
6
100 0.060
Total 0.746
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Sand Requirements
Volume of sand = 1.000 – 0.746 = 0.254 yd³
Mass of sand = volume X density
Mass of sand = 0.254 X 4448 = 1130 lb(SSD)
Fine Agg. Content(SSD) = 1130 lb/yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Mixture Proportions
Material Content
(lb/yd³)
Cement 712
Water 242
Coarse Agg.(SSD) 1845
Fine Agg.(SSD) 1130
Total Mass. 3929
WRA 39 fl.oz./yd³
AEA 7 fl.oz./ yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Moisture Corrections
Mbatch = MSSD X 1 + mc
1 + abs
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Moisture Corrections
Mbatch = MSSD X 1 + mc
1 + abs
Coarse Aggregate
Mbatch = 1845 X 1.020 = 1873 lb/yd³
1.005
Fine Aggregate
Mbatch = 1130 X 1.035 = 1159 lb/yd³
1.009
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Moisture Corrections
Wcorr = MSSD X (abs – mc)
1 + abs
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Moisture Corrections
Wcorr = MSSD X (abs – mc)
1 + abs
Coarse Aggregate
Wcorr = 1845 X (.005 - .020) = -28 lb/yd³
1.005
Fine Aggregate
Wcorr = 1130 X (.009 - .035) = -29 lb/yd³
1.009Total water correction = 28 + 29 = 57 lb/yd³
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Mixture Proportions
Moisture Batch
Corrections Proportions
Cement 712 lb/yd³ 712 lb/yd³
Water 242 lb/yd³ -57 185 lb/yd³
CA(SSD) 1845 lb/yd³ +28 1873 lb/yd³
FA(SSD) 1130 lb/yd³ +29 1159 lb/yd³
Total Mass 3929 lb/yd³ 3929 lb/yd³
WRA 39 fl.oz./yd³ 39 fl.oz./yd³
AEA 7 fl.oz./yd³ 7 fl.oz./yd³
OK
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Trial Batch
For a 2 cubic foot (0.074 yd³) batch:
Batch
Quantities
Cement 712 lb/yd³ X 0.074 52.688 lb
Water 185 lb/yd³ X 0.074 13.690 lb
C.A. 1873 lb/yd³ X 0.074 138.602 lb
F.A. 1159 lb/yd³ X 0.074 85.766 lb
Total Mass 3929 lb/yd³ X 0.074 290.746 lb
WRA 39 fl.oz./yd³ X 0.074 2.89 fl.oz.
AEA 7 fl.oz./yd³ X 0.074 0.51 fl.oz.
11.0 Moisture
1.0 Strength
2.0 W/CM
3.0 Stone
4.0 Air
5.0 Slump
6.0 Water
7.0 Cement
8.0 Type
9.0 Admixture
10.0 Sand
12.0 Trials
Trial Batch
Trial batches tested for:
• Slump
• Air Content
• Strength
Adjustments made:
• Water Content
• Admixture Dose
• Cement Content
• Sand Content
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