Intro to Concrete Mix Design

Intro to Concrete Mix Design NH 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 Mixtures Factors to be considered • • • • • •

Workability Placement conditions Strength Durability Appearance Economy

Designing Concrete Mixtures Factors 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

Proportioning Absolute 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 volume

1yd 1yd 1yd

weight

Concrete is batched by weight

Concrete is sold by volume volume

Absolute Volume Material

Volume (yd3)

Density (lb/ yd3)

Mass (lb)

Air Water Cement Sand Stone

0.060 0.150 0.111 0.245 0.434

1685 5319 4455 4455

253 590 1095 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 Requirement Specified 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 Codes 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 deicing chemicals Corrosion protection of reinforcement in concrete exposed to chlorides

0.45

4500

0.40

5000

Requirements For Sulfate Exposure Sulfate Exposure

Max. W/CM

Min. f’c psi

Negligible

----

----

Moderate

0.50

4000

Severe Very Severe

0.45 0.40*

4500 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 Deviation If only 15 to 29 consecutive test are availablemultiply 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 WaterCement Ratio The W/CM is determine from: • Durability considerations • Required strength

Requirements of ACI 318 Building Codes 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 deicing chemicals Corrosion protection of reinforcement in concrete exposed to chlorides

0.45

4500

0.40

5000

Requirements For Sulfate Exposure Sulfate Exposure

Max. W/CM

Min. f’c psi

Negligible

----

----

Moderate

0.50

4000

Severe Very Severe

0.45 0.40*

4500 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 7000

W/CM Non-air

W/CM Air

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 Size For 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 Bulk volume of dry-rodded coarse aggregate per unit volume of concrete for different FM (in.) of fine aggregate --------

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 Coarse Aggregate • Values in table are based on aggregate in a dryrodded 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 Content The amount needed depends on: • Max aggregate size – Less paste as size increases

• Level of exposure

Effect of air content on water demand: Rule of thumbDecrease 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 3

Slump Min 1

Plain footings, caissons, and Substructure walls Beams & reinforced walls

3

1

4

1

Columns

4

1

Pavements and slabs

3

1

Mass concrete

3

1

Reinforced walls & footings

Water Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water 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 Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water demand is influenced by: • • • • •

Slump requirement Aggregate size Aggregate shape Air content Cementing materials content • Temp • Admixtures – Water-reducing – Mid & High range

Water Content Water requirement for Non-Air-Entrained concrete: Nominal Max Aggregate Size(inches) 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

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 Content Effects 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 Content •

Cement 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 Content General 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 Content General recommendations(PCA):

• For workability, finishability, and durability in flatwork cementitious material to follow recommendations in table: Max Aggregate

Min Cement

(inches)

(lbs)

1-1/2 1

470 520

3/4 1/2 3/8

540 590 610

Cement Content • Quality depends mainly on w/cm & the water content should 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 & airentraining admixtures – SCM’s(fly ash & slag)

Cement Content • Quality depends mainly on w/cm & the water content should 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 & airentraining admixtures – SCM’s(fly ash & slag)

Cement Content • Quality depends mainly on w/cm & the water content should 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 & airentraining admixtures – SCM’s(fly ash & slag)

Aggregate Retained Chart 8 -18

Cement Content • Quality depends mainly on w/cm & the water content should be held to a minimum to reduce Coarseness Factor cement content by using: Coarseness Factor  % of total that is retained on 3/8 in. sieve and larger 100 – Largest practical max aggregate size – Optimum aggregate gradation – Optimum ratio of fine to coarse aggregate – Water-reducing & airentraining admixtures – SCM’s(fly ash & slag)

% of total that is retained on the #8 sieve and larger 11.7%  25.0%  12.5%   100 11.7%  25.0%  12.5%  7.1%  5.0% 49.2%   100 61.3%  80.3

Cement Content • Quality depends mainly on w/cm & the water content should be held to a minimum to reduce Workability Factor cement content by using: Workability Factor  % of total that passes the #8 sieve  2.5  cm  565 lb/yd  3

– Largest practical max aggregate size – Optimum aggregate gradation – Optimum ratio of fine to coarse aggregate – Water-reducing & airentraining admixtures – SCM’s(fly ash & slag)



 623  565 lb/yd3  38.6%  2.5   94 lb/yd3   58 lb/yd3  38.6%  2.5   94 lb/yd3   40.1

  

  

94 lb/yd3



Cement Content • Quality depends mainly on w/cm & the water content should 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 & airentraining admixtures – SCM’s(fly ash & slag)

Cement Content • Quality depends mainly on w/cm & the water content should 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 & airentraining admixtures – SCM’s(fly ash & slag)

Admixture Effects The 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 content should 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 & airentraining 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

Moderate

II,MS,IP(MS),IS(MS),P(MS), I(PM)(MS),I(SM)(MS)

Severe

V(HS)

Very Severe

V(HS)

Cement Type The 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 Materials Cautions • 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 ASTM C 618 (AASHTO M 295)

Fly Ash

• Class F—Fly ash with pozzolanic properties • Class C—Fly ash with pozzolanic and cementitious properties

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 ASTM C 989 (AASHTO M 302)

• Grade 80 Slags with a low activity index • Grade 100 Slags with a moderate activity index • Grade 120 Slags with a high activity index

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 – Class F

• Slag • Silica fume • Calcined clay – Metakaolin

• Calcined shale

15% to 40% 15% to 25%

20% to 70% 5% to 10% 15% to 35% 10%

15% to 35%

Effects of SCMs on Freshly Mixed Concrete Reduced Increase

no/little effect varies

Water requirements

Workability Bleeding & segregation Air content Heat of hydration Setting time Finishability Pumpability Plastic shrinkage cracking

Fly ash

Slag

Silica Fume

Effects of SCMs on Hardened Concrete Reduced Increase

no/little effect varies

Strength gain Abrasion resistance Freeze thaw/scaling resistance

Drying shrinkage Permability Alkali silica reactivity Chemical resistance Carbonation Concrete color

Fly ash

Slag

Silica Fume

Effect On Reducing ASR ASTM 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 Type The 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 Type ACI 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 Mass Proportions(lb/yd³) • Cement content • Water content • Coarse aggregate

Already determined

• 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

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 Example Conditions & 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 Example Conditions & Specifications

• 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%

• Fine aggregate – Natural sand – S.G. = 2.64(SSD) – Fineness modulus, FM = 2.70 – Absorption, abs. = 0.9% – Moisture content, mc = 3.5%

Absolute Volume Example Conditions & 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

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 11.0 Moisture 12.0 Trials

From this information a trial mixture is proportioned to meet the conditions and specifications

1.0 Strength 2.0 W/CM 3.0 Stone

Specified strength for design = 3500 psi Note requirements of ACI 318 Building Code

4.0 Air

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

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

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

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

9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

F’cr = 4500 + 1200 = 5700 psi

1.0 Strength

W/CM required for strength

2.0 W/CM

Required Strength f‖cr

W/CM Non-air

W/CM Air

5.0 Slump

7000

0.33

----

6.0 Water

6000

0.41

0.32

3.0 Stone 4.0 Air

7.0 Cement 8.0 Type 9.0 Admixture

5700

0.34

5000

0.48

0.40

4000

0.57

0.48

3000

0.68

0.59

2000

0.82

0.74

10.0 Sand 11.0 Moisture 12.0 Trials

1.0 Strength

W/CM required for durability

2.0 W/CM 3.0 Stone

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

4.0 Air 5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

W/CM = 0.34 is to be used

1.0 Strength

Bulk Volume of Coarse Aggregate

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 11.0 Moisture 12.0 Trials

Max Size (in.)

Bulk volume of dry-rodded coarse aggregate per unit volume of concrete for different FM of fine aggregate

--------

2.40

2.60 2.70 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

0.65

1½

0.75

0.69 0.68 0.67 0.73 0.71

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

0.69

1.0 Strength

Mass of Coarse Aggregate

2.0 W/CM 3.0 Stone

Oven dry mass = bulk volume X bulk density 4.0 Air 5.0 Slump

Oven dry mass = 0.68 X 1650 = 1836 lbs

6.0 Water

Mass in SSD = 1836 X 1.005

7.0 Cement 8.0 Type

absorption

9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Coarse Aggregate Content(SSD) = 1845 lbs

1.0 Strength

Specified Air Contents (tolerance +/- 1.5%) Air required = 6.0% +/- 1.5%

2.0 W/CM 3.0 Stone 4.0 Air

Nominal Maximum Aggregate Size(in.) Exposure

5.0 Slump 6.0 Water

--------

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

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

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 11.0 Moisture 12.0 Trials

Slump specified at 3 in. +/- 1 in.

1.0 Strength 2.0 W/CM

Water Requirements(lbs/yd³) for air-entrained concrete

3.0 Stone 4.0 Air 5.0 Slump 6.0 Water

7.0 Cement

Nominal Max Aggregate Size(inches)

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

8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

1.0 Strength 2.0 W/CM

Water Requirements(lbs/yd³) for air-entrained concrete

3.0 Stone 4.0 Air 5.0 Slump

295

-

(from table)

35

=

260

=

242

(for rounded gravel with some crushed particles)

6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

260

-

18

(7% reduction for water Reducing admixture)

Water content = 242 lb/yd³

1.0 Strength 2.0 W/CM 3.0 Stone 4.0 Air

Cement Content Requirements

Cement content = Water content W/CM

5.0 Slump 6.0 Water

7.0 Cement

Cement content = 242 0.34

8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Cement content = 712 lb/yd³

1.0 Strength 2.0 W/CM

Cement Type Requirement

3.0 Stone 4.0 Air

No special requirements

5.0 Slump

Type I (ASTM C 150) 6.0 Water

7.0 Cement

Use either

Type GU (ASTM C 1157)

8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Note: if SCM are used ensure that proportions do Not exceed limits of ACI 318 Building Codes for Concrete exposed to deicer salts

1.0 Strength 2.0 W/CM

Admixture Requirements

3.0 Stone 4.0 Air 5.0 Slump

Water-reducer dose 5.5 fl. oz. / 100 lb X 712 lb/yd³ = 39.0 fl. oz./yd³

6.0 Water

Air-entrainment dose 7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

1.0 fl. oz. / 100 lb X 712 lb/yd³ = 7.0 fl. oz./yd³

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Material

Mass (yd³)

Density (lb/ yd³)

Cement

712

5308

Water Stone (SSD)

242

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Air Total

1845

6% by volume

Volume (yd³)

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Material

Mass (yd³)

Density (lb/ yd³)

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

Cement

712

Water Stone (SSD)

242

10.0 Sand 11.0 Moisture 12.0 Trials

Air Total

1845

6% by volume

5308

Volume (yd³) 712 5308

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Material

Mass (yd³)

Density (lb/ yd³)

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

Cement

712

Water Stone (SSD)

242

10.0 Sand 11.0 Moisture 12.0 Trials

Air Total

1845

6% by volume

5308

Volume (yd³) 712 5308

0.134

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Material

Mass (yd³)

Density (lb/ yd³)

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

Cement

712

5308

Water Stone (SSD)

242

1685

1845

4516

10.0 Sand 11.0 Moisture 12.0 Trials

Air Total

6% by volume

Volume (yd³) 712 5308 242 1685 1845 4516

6 100

0.134

0.143 0.409 0.060

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Material

Mass (yd³)

Density (lb/ yd³)

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

Cement

712

5308

Water Stone (SSD)

242

1685

1845

4516

10.0 Sand 11.0 Moisture 12.0 Trials

Air Total

6% by volume

Volume (yd³) 712 5308 242 1685 1845 4516

6 100

0.134

0.143 0.409 0.060 0.746

1.0 Strength

Sand Requirements

2.0 W/CM 3.0 Stone 4.0 Air

Volume of sand = 1.000 – 0.746 = 0.254 yd³

5.0 Slump 6.0 Water

Mass of sand = volume X density

7.0 Cement 8.0 Type

Mass of sand = 0.254 X 4448 = 1130 lb(SSD)

9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Fine Agg. Content(SSD) = 1130 lb/yd³

1.0 Strength

Mixture Proportions 2.0 W/CM 3.0 Stone 4.0 Air

Material

Content (lb/yd³)

5.0 Slump

Cement

712

Water

242

8.0 Type

Coarse Agg.(SSD)

1845

9.0 Admixture

Fine Agg.(SSD)

1130

10.0 Sand

Total Mass.

3929

6.0 Water

7.0 Cement

11.0 Moisture 12.0 Trials

WRA AEA

39 fl.oz./yd³ 7 fl.oz./ yd³

1.0 Strength

Moisture Corrections 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 11.0 Moisture 12.0 Trials

Mbatch = MSSD X 1 + mc 1 + abs

1.0 Strength

Moisture Corrections 2.0 W/CM 3.0 Stone

Mbatch = MSSD X 1 + mc 1 + abs

4.0 Air 5.0 Slump 6.0 Water

7.0 Cement 8.0 Type

Coarse Aggregate

Mbatch = 1845 X 1.020 = 1873 lb/yd³ 1.005 Fine Aggregate

9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Mbatch = 1130 X 1.035 = 1159 lb/yd³ 1.009

1.0 Strength

Moisture Corrections 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 11.0 Moisture 12.0 Trials

Wcorr = MSSD X (abs – mc) 1 + abs

1.0 Strength

Moisture Corrections 2.0 W/CM 3.0 Stone

Wcorr = MSSD X (abs – mc) 1 + abs

4.0 Air 5.0 Slump 6.0 Water

Coarse Aggregate

Wcorr = 1845 X (.005 - .020) = -28 lb/yd³

7.0 Cement

1.005 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

Fine Aggregate Wcorr = 1130 X (.009 - .035) = -29 lb/yd³ 1.009 Total water correction = 28 + 29 = 57 lb/yd³

1.0 Strength

Mixture Proportions 2.0 W/CM

Moisture Corrections

3.0 Stone 4.0 Air

Batch 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

WRA AEA

39 fl.oz./yd³ 7 fl.oz./yd³

5.0 Slump 6.0 Water

7.0 Cement 8.0 Type 9.0 Admixture

10.0 Sand 11.0 Moisture 12.0 Trials

OK

3929 lb/yd³ 39 fl.oz./yd³ 7 fl.oz./yd³

1.0 Strength

Trial Batch 2.0 W/CM

For a 2 cubic foot (0.074 yd³) batch:

3.0 Stone 4.0 Air

Batch Quantities

5.0 Slump 6.0 Water

7.0 Cement

Cement Water C.A. F.A.

712 lb/yd³ 185 lb/yd³ 1873 lb/yd³ 1159 lb/yd³

X X X X

0.074 0.074 0.074 0.074

Total Mass

3929 lb/yd³ X 0.074

52.688 lb 13.690 lb 138.602 lb 85.766 lb

8.0 Type 9.0 Admixture

290.746 lb

10.0 Sand 11.0 Moisture 12.0 Trials

WRA AEA

39 fl.oz./yd³ X 7 fl.oz./yd³ X

0.074 0.074

2.89 fl.oz. 0.51 fl.oz.

1.0 Strength

Trial Batch 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 11.0 Moisture 12.0 Trials

Trial batches tested for: • Slump • Air Content • Strength Adjustments made: • Water Content • Admixture Dose • Cement Content • Sand Content

Thank You www.portcement.org www.concrete.org