Performance Engineered Mixtures

1

Dr Peter Taylor, PE (IL)

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 1 of 47

Design is more than copy/paste

• The mix• The test• The spec

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 2 of 47

What Do We Want?

• The Owner wants:Strong enoughCrack freeAbility to resist the environmentSafetyCost effective

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 3 of 47

What Do We Want?

• The Contractor wants:The right workability for his machine

(water content, agg gradation)Control of the setting time (SCM type)Cost effective

WCPA Annual Concrete Pavement Workshop

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What is concrete?• Aggregates• Cement• Supplementary cementitious materials• Water• Admixtures

5

WCPA Annual Concrete Pavement Workshop

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But I have been doing it this way for 30 years…

WCPA Annual Concrete Pavement Workshop

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Proportioning ApproachesPast

• Structural concrete 1:2:4 • Other concrete 1:3:6• Waterproof concrete Add salt

• No chemicals• No SCMs• Precision was ugly• Bulking made it worse

WCPA Annual Concrete Pavement Workshop

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• Developed Before water reducersBefore supplementary cementitious

materials• Primarily focused on structural concrete100 mm (4”) slump30 MPa (~4000 psi)

• ACI 211 last revised in 1991Linear

Proportioning ApproachesPresent

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 8 of 47

Absolute Volume Approach

• Paste volume based on coarse aggregate size

• Coarse aggregate volume based on subtracting the fineness modulus (FM) of sand from a fudge factor

• Fill the remaining volumewith sand

• Linear process

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 9 of 47

Koehler

Proportioning ApproachesFuture

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Choose the Aggregate System• Combined gradation• Determine void ratio

WCPA Annual Concrete Pavement Workshop

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Aggregate System• Tarantula Curve (Ley)

WCPA Annual Concrete Pavement Workshop

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Aggregate System• 50/50 – void ratio 27.1%• Tarantula – void ratio 25.3%

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Choose a Paste System for Performance

• Cementitious blend• W/Cm• Air content

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Choose Paste Volume• All voids must be filled with paste• And a bit more to coat the particles

for workability

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Choose Paste Volume• Need enough paste for base workability

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Choose Paste Volume• Need enough paste for mechanical

properties ~125 - 175% of voids

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Put it all together

• Measuring workability

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Put it all togetherTarantula 50/50

Void ratio 125 150 125 150 175Cementitious 427 505 424 500 543

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Proposed Mixture Proportioning Procedure

Input aggregates

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Proposed Mixture Proportioning Procedure

Check aggregates

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Input paste parameters

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Proposed Mixture Proportioning Procedure

Calculate proportions

WCPA Annual Concrete Pavement Workshop

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Proposed Mixture Proportioning Procedure

Check proportions• Check workability• Check air

• Adjust paste volume

• Check hardened properties

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• Do we know what’s in there?

WCPA Annual Concrete Pavement Workshop

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What do we need to measure?

• What is the potential distress?Tougher environmentsNew materialsNew practices

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• VKelly – workability response to vibration

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• The Box – workability response to vibration

• Edge slump vs honeycomb

Ley

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• Calorimetry tells us about the chemistry of

the system (Uniformity)

Hydration Profile

0.00

3.00

6.00

9.00

12.00

15.00

0:00:00 6:00:00 12:00:00 18:00:00 24:00:00

Time of Hydration (hrs)

J/gh

Sample "5P"Sample "5C"Sample "5F"Sample "5S"

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• Unit weight – something is wrong

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• Super Air Meter (SAM)• Air void system in fresh

concrete

Ley

WCPA Annual Concrete Pavement Workshop

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Test Methods

• Tests• Ultrasonic Pulse Velocity (UPV)• Setting and therefore sawing time

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 32 of 47

Test Methods

• Tests• Ultrasonic Pulse Velocity (UPV)• Setting and therefore sawing time

y = 0.9891x + 219.01R² = 0.8997

y = 1.0227x + 299.05R² = 0.8114

0

200

400

600

800

1000

1200

0 50 100 150 200 250 300 350 400 450

Saw

tim

e, m

inut

es

UPV Initial Set, minutes

IA Early EntrySawConventional Saw

LATE

MN Early

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Test Methods

• Tests• Maturity – strength development up to 24

hours

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Test Methods

• Tests• Resistivity – Potential Durability

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Test Methods

• Sensors• Movement• Temperature• Moisture• Chemicals

Ceylan

Slowik

WCPA Annual Concrete Pavement Workshop

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What do we want to measure?

• Critical Properties at design / proportioning stage

• Uniformity at deliveryTesting3’rd party records

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AASHTO Guide Specification

• Based on existing specs• Add new thinking• Take out some stuff

WCPA Annual Concrete Pavement Workshop

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Materials

• Cement – M85, M240• Slag cement – M302• Fly ash – M295 (ASTM C 1709)• Admixtures – M154, M194 (others?)

WCPA Annual Concrete Pavement Workshop

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Materials• AggregatesM80 for contaminantsPP65 for ASR Local practice For d-cracking

Continue with current individual fraction gradation

Address combined gradation in proportioning

ASTM C 1761 for IC

WCPA Annual Concrete Pavement Workshop

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PrescriptiveProperty Value AASHTO Test

Method When Test Must be Conducted*

Combined Aggregate Gradation

Within Tarantula Curve T27 All

#8 - #30 >15% 24% < #30 - #200 < 34% Cementitious content 400 lb/yd3, minimum Batch records Mixture design

658 lb/yd3, maximum Batch records Mixture design Portland cement content 50% of cementitious,

minimum Batch records Mixture design

Class C Fly Ash** 30% maximum cement replacement

Batch records Mixture design

Class F Fly Ash** 25% maximum cement replacement

Batch records Mixture design

GGBFS** 50% maximum cement replacement

Batch records Mixture design

w/cm ratio [0.42] […] maximum Batch records All

Entrained air 4% after placement, and T 152, T 196M/T 196,or T 199

All

0.2 SAM number Super-air-meter All

2% maximum loss during placement

T 152, T 196M/T 196,or T 199

All

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 41 of 47

Performance

Property Value AASHTO Test Method

When Test Must be Conducted

Electrical Resistivity [27] […] kΩ-cm minimum at [28] […] days

TP 95 All

Compressive strength [4000] [3500] […] psi minimum at [28] [90] days

T 22 All

Freeze thaw resistance RDM > [80] […] % C666 Mixture design

Shrinkage Crack free at [14] […] days

ASTM C 1581 Ring

Mixture design

<0.06 % ASTM C 157 mod**

Mixture design

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 42 of 47

ReportProperty AASHTO Test Method Modulus of elasticity at 28 days

ASTM C 469

Drying shrinkage ASTM C 157 Coefficient of thermal expansion

T 336

Rate of strength development to 90 days

T 22

Rate of development of electrical resistivity

TP 95

Unit weight T 121

Slump T119

WCPA Annual Concrete Pavement Workshop

Peter Taylor Presentation February 13, 2015 43 of 47

QCProperty AASHTO Test Method When Test Must be Conduc

Air void system Foam Drainage Mixture design

Slump Within 1” of design mix T 119M/T 119

Unit weight Within 3 pcf of design mix

T 121

Calorimetry Adiacal Construction

Maturity ASTM C 1074 Construction

Strength development T 22 Construction

Resistivity Development TP 95 Construction

WCPA Annual Concrete Pavement Workshop

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Quality

• Saves money and heartburn• Defines risk and responsibility• Needs “good” tests

WCPA Annual Concrete Pavement Workshop

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Closing• Did you get what you thought you paid for?

• Did you measure what you really want?

• Concrete can last a long time…

Chicago Sun Times

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Discussion…

WCPA Annual Concrete Pavement Workshop

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