SEAONC CONSTRUCTION QUALITY ASSURANCE COMMITTEE

Art Dell, PE SOHA Engineers

Guidelines For Reviewing Concrete Mix Designs

SE University, December 10, 2014 www.LearnWithSEU.com

Find a a copy of the Guidelines by googling:

“Guidelines for Reviewing Concrete Mix Designs”

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CONSTRUCTION QUALITY ASSURANCE COMMITTEE

Design engineers Engineers that work at inspection and

testing agencies “…issues related to the quality of the

construction process with an emphasis on testing and inspection issues.”

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THE “GUIDELINES”

The submittal process

The review process

Where it goes from here

Appendix A Annotated Samples

Appendix B Performance and Code Considerations

Appendix C Specifications

Appendix D Review of Mix Design Strengths

Appendix E Definitions

Appendix F References

Appendix G Aggregate Report

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HANDOUTS

“ACI HANDOUT”

“GUIDELINES HANDOUT”

CONCRETE MIX DESIGN SUBMITTAL The Review Process

Specifying Concrete

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THE CONCRETE SUPPLIER

THE STRUCTURAL ENGINEER

THE TESTING AND INSPECTION AGENCY

CONCRETE MIX DESIGNS

WHO PREPARES THEM?

WHO REVIEWS THEM?

A REGISTERED ENGINEER?

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PROPORTIONING CONCRETE MIXES

THE CONCRETE SUPPLIER WILL USE: Experience Knowledge of the materials Knowledge of the project requirements ACI 211.1:

Standard Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete

Estimated Weight Method Absolute Volume Method

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CONCRETE MIX DESIGNS –

SPECIFICATION APPROACH

PRESCRIPTIVE SPECIFICATION: Compressive Strength Aggregate Source and Gradation Quantity of Cement per Cubic Yard Maximum Water/Cement Ratio Slump

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CONCRETE MIX DESIGNS –

SPECIFICATION APPROACH

PERFORMANCE SPECIFICATION: Compressive Strength Durability - Exposure Class Nominal Maximum Aggregate Size Shrinkage Limitations

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PERFORMANCE SPECIFICATION

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PERFORMANCE SPECIFICATION

EXPOSURE CATEGORIES

F2 MODERATE FREEZING AND THAWING

S0 SULFATE EXPOSURE NOT APPLICABLE

P1 LOW PERMEABILITY REQUIRED

C3 MODERATE CHLORIDE EXPOSURE

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CONCRETE MIX DESIGNS –

SPECIFICATION APPROACH

NATIONAL READY-MIXED CONCRETE ASSOCIATION -

“P2P INITIATIVE”

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PERFORMANCE SPECIFICATION

WATER

CEMENT

SUPPLEMENTAL CEMENTITIOUS MATERIALS FLY ASH GROUND GRANULATED BLAST FURNACE SLAG SILICA FUME METAKAOLIN

w/c = Ratio of the mass of water to the mass of portland cement w/cm = Ratio of the mass of water to the mass of cement plus the supplemental cementitious materials (SCM)

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LOW W/CM RATIO = NO CRACKS?

HIGH CEMENT CONTENT = MORE CRACKS?

Submittals help us verify that the contractor is interpreting the construction documents correctly… Construction documents include the drawings and specifications…

So… Get out the plans and specs

And…

ACI 318 and your books of ASTM Standards 16

THE SPECIFICATIONS GOVERN THE SUBMITTALS

Division 1 - Section 01 3X 00 “Submittals” Administrative Requirements:

Review Time Types of Submittals: Product Data Certifications Test Results

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CONCRETE SPECIFICATIONS

Section 03 30 00 – Cast-in-Place Concrete Section 03 05 15 – Portland Cement Concrete Part 1 General Part 2 Products Part 3 Execution

Submittals Quality Assurance

Concrete Materials Concrete Mixes

Placement, finishing, etc

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DRAWINGS MAY ALSO HAVE NEEDED INFORMATION Concrete strength requirements

Concrete “Class” identification

What concrete mix goes where

CHECK THE GENERAL NOTES

CHECK THE STEEL DECK SCHEDULE

Class 3500-3/4

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The Mix Design Submittal - Is it Complete and Responsive?

Is it for you? Has the Contractor reviewed and stamped it? Are all the items requested included? Does it include all mixes? Does it indicate where each mix is to be used?

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Do not hesitate to: Return it un-reviewed if it is obviously incomplete or unresponsive Contact the Architect to discuss missing information Ask for permission to contact the contractor or supplier

directly for clarifications. Only review items that are your responsibility MSDS?

LEED? 21

THREE QUESTIONS Does the mix meet the performance requirements of the specifications with respect to strength and other characteristics such as shrinkage, permeability, w/cm ratio, etc? Is the historical or trial batch test data adequate to justify the strength? Do the materials used comply with the project requirements as evidenced by test results, certifications, and product data?

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27.001 Cubic Feet

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6-sack, 4000 psi

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“Saturated Surface Dry”

ASTM C 150 Cement Types: Type I – least restrictive Type II – moderate sulfate resistance Type III – high early strength Type IV – low heat of hydration Type V – high sulfate resistance

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Relative percentages of coarse and fine aggregates

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Dosage rate shown in manufacturer’s recommendations is generally given in ounces per

“hundredweight” of cementitious materials

FRESH UNIT WEIGHT 122.39

AIR 6.0%

EQUILIBRIUM UNIT WEIGHT CAN BE CALCULATED USING ASTM C 567 30

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ASTM C330 – Lightweight Aggregates

Splitting Tensile Strength 310 psi Min

QUALIFYING A MIX ON THE BASIS OF

STRENGTH

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The Required Average Strength – f’cr is the key concept here

QUALIFYING A MIX ON THE BASIS OF

STRENGTH

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The Required Average Strength is always greater than the

specified strength

THE REQUIRED AVERAGE STRENGTH CONCEPT

IS BASED ON:

• Limiting the probability to no more than 1-in-100 that: – The average of any three consecutive

strength tests taken during construction will be below the specified strength;

– AND – Any single strength test will be more than

500 psi below the specified strength. 34

DETERMINING REQUIRED AVERAGE STRENGTH

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DETERMINING REQUIRED AVERAGE STRENGTH

USING TABLE 5.3.2.2

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DETERMINING REQUIRED AVERAGE STRENGTH

USING A FIELD STRENGTH RECORD

STEP 1 – CALCULATE STANDARD DEVIATION

VARIABILITY OF STRENGTH TESTS RELATED TO:

UNIFORMITY OF MIX PLANT QUALITY CONTROL

STEP 2 – CALCULATE REQUIRED AVERAGE USING TABLE 5.3.1.2

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DETERMINING REQUIRED AVERAGE STRENGTH

USING A FIELD STRENGTH RECORD

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DETERMINING REQUIRED AVERAGE STRENGTH

USING A FIELD STRENGTH RECORD

5.3.1.1 (continued)

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The modification factor for a 15-test record is 1.16 – see Table 5.3.1.2

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CALCULATING REQUIRED AVERAGE STRENGTH

f’cr = 4540 psi

versus 4000 + 1200 = 5200 psi

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5.3.3 - Documentation of Average Compressive Strength - Summary

Data from actual proposed mix not required Similar mix OK – just like for f’cr As few as 10 tests are acceptable

Must be consecutive tests Must be from a minimum 45-day period

Often the same test record is used

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5.3.3.2 - Documentation of Average Compressive Strength by Trial Mixtures

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5.3.3.2 - Documentation of Average Compressive Strength by Trial Mixtures

Commentary (b) For concrete made with more than one type of

cementitious material, the concrete supplier must establish not only the water-cementitious material ratio but also the relative proportions of cementitious materials and admixtures, if any, that will produce the required average compressive strength and satisfy the durability requirements of Chapter 4. This will require multiple trial batches with different mixture proportions. The exact number of batches will depend on the number of cementitious materials and the range of their relative proportions.

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Com

pres

sive

Stre

ngth

W/CM Ratio

f’cr = 4000 + 1200 = 5200 psi

5200 psi line

Yields 0.52 W/CM

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“conforms to…ASTM specification C33”

No signature…

C 33 Requires: Clay and Friables Lt. Wt. Particles Abrasion Loss Soundness

Alkali-Silica Reactivity:

ASTM C 295 ASTM C 289

2.3 to 3.1

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C 33 Requires: Sieve analysis Organic Impurities Mat’l < #200 sieve

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…meets or exceeds…ASTM C 150, Type I, II, IV…, Low-alkali; ASTM C 1157, Type GU

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…meets… ASTM C 618 for Class F fly ash

Other Submittal Items Admixture Product Data or Certification Slag Cement Certification Shrinkage Test Reports Permeability Test Report Total Chloride Calculations or Test Results Thermal Control Plan

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Sustainability LEED Local Materials (cement, aggregates, fly ash) Recycled Materials (fly ash, slag cement, recycled concrete aggregates) Slag Cement or White Cements to lighten the color can reduce interior lighting requirements and mitigate the heat island effect

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Sustainability INTERNATIONAL GREEN CONSTRUCTION CODE

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QUESTIONS?

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SEAONC CONSTRUCTION QUALITY ASSURANCE COMMITTEE

Art Dell, PE SOHA Engineers

Guidelines For Reviewing Concrete Mix Designs

SE University, December 10, 2014 www.LearnWithSEU.com

CHALLENGE QUESTION:

Which Appendix from the Guideline is the answer to this session’s Challenge Question?

A. Appendix A Annotated Samples B. Appendix B Performance and Code Considerations C. Appendix C Specifications D. Appendix D Review of Mix Design Strengths

Please circle the answer that is announced so that you can use the information to complete your quiz (NY) or form (FL) for PDH.