Standards for Concrete

Materials & Portland

Cement Concrete PavingWhat they do and don’t tell us

September 2015

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Toy S. Poole

Education: BS Chemistry, PhD Zoology

32 y - Corps of Engineers Retired 2010

Live in Austin, Texas

Currently employed: CTL Group

ASTM since 1985 Committees C1 (cement) and

C9 (concrete)

Board of Directors

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Objective and Scope

Discuss important properties of standards

Compare with realities

Present selected examples for PCCP

Materials

Construction

FAA P-501

UFGS 32 13 11

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Origins

First Concrete Rd

Standards Org’s

ASTM C1 1902

ASTM C9 1914

AASHTO 1914

ACI 1904

State & Fed Gov’t

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Bellafontaine, OH - 1891

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Role of Standards

Translate what we think we know

Experience

R&D

Into effect construction practices

Much success

A way to go yet

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Types of Standards

Specifications (mandatory)

Materials

Construction

Test Methods (mandatory)

Practices (mandatory)

Collection of alternative test methods & specs

Guides & State of Art Reports (not mandatory)

Generally advisory

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What Makes a Good Standard

Specifications

Clearly defined requirements

Quantifiable

Verifiable

Relevant

Test Methods

Relevant

Precision and bias

Economically manageable

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A few general topics

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Myth about Standards

Old standards

perfected practice

Specification limits

field validated

Details of test methods

extensively vetted

P&B is adequate for the job

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How Standards Go Wrong

No applicable standard exists

Stds exists but not relevant to the problem

Precision (and Bias) problems

Fossilization

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Origin of Specification Limits

Laboratory research

Accumulated Experience

Field Service Record

Crony capitalism

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Field Service Records – Gold Standard

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Field Service Records

Good concept –

Effective for short-

term performance

Less effective for

long-term

assessment

Records scarce

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A Little About P&B

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Variation

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100mean

stdCV

Standard deviation from mean

Mean

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False Rejection

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standard deviation from mean

pro

babili

ty o

f occurr

ence

Max limit

P(false rejection)

True Value

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False Pass

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standard deviation from mean

pro

babili

ty o

f occurr

ence

Max limit True Value

P(false pass)

Materials

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Materials Standards Relevant to PCCP

Cement

SCM’s

Aggregates

Curing materials

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A Word on Mill Certificates for Materials

Commonly used for acceptance

Usually give a general indication of properties

Never (?) reveal a compliance problem

Independent verification is costly and not

schedule friendly

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Cements

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Cement Specfications

ASTM C 150 (1940)

Portland Cement

ASTM C 595 (1967)

Blended Cements

ASTM C1157 (1992)

Performance specification

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Supplemental Cementitious Materials (SCM)

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SCM Specifications

C618 (1968) - Coal fly ash and natural

pozzolans

C1240 – Silica fume – not so much

C989 – Slag cement – commonly used

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Coal Fly Ash

Class C –

Lots of personality

Setting, workability

durability

Class F –

Little personality

Variability

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Origins of C v F?

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Aggregates - ASTM C 33 (1921)

AAR

Issues – F/T durability

Much due to within-quarry variation

Not usually covered by project spec’s

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Quarry Variability

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AAR

Brief history

Current guidance

ASTM C1778

AASHTO PP65

Problems yet

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Durability of Aggregate D-Cracking

ASTM Method C666

P&B

Good concept

Marginal

Economically

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Aggregate Durability - Popouts

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Aggregate Durability – Surface Damage

UFGS 32 13 11

≤1% total del.mtls.

Clearly described

Long Test Method

Marginal economically

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Curing Compounds (ASTM C 156)

Clever test concept

P&B !!!!

Limit = 0.55 kg/m2

Std = 0.30 kg/m2

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Evaporation Reducers

No specs

No test methods

Testimonials on field performance

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Construction Specifications

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Some Problem Properties

Strength

Consolidation

Curing

Edge slump

Excess surface

mortar

Plastic Shrinkage

Grinding

Latent defects

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Strength - ASTM C78 (1930)

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Reputation for poor

precision

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Poor Consolidation

No test methods for detection

Visual - Free edge of pilot lanes

Visual on vibrator trails, surface features

P-501 cites ASTM C642 (density)

If problems suspected

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Types of Poor Consolidation

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Types of Poor Consolidation

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P C601 Test Method – C642

Mass air (Ma)

Mass water (Mw)

Ma– Mw = volume (V)

Density = Ma/V

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Plastic Shrinkage Cracking

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Plastic Shrinkage Cracking

Evaporation > Bleeding

ACI 305R

Critical evaporation

threshold: 0.2 lb/ft2/h

Based on old concrete

technology

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Curing Compound Application

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Curing Compound Application

Project Spec Application Rate

Typically 200 ft2 per gal

No reliable method of measuring

Timing of application can be important

>Final finishing – classical guidance

Typically applied very soon after the paver.

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Early Curing Compound Application

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Measuring Edge Slump

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Edge Slump

Method is relatively well defined in project

spec’s.

12’ straight edge

Details on when and where…

Limit ≤6mm (1/4 in)

We don’t know the precision of this method

6 mm is a small amount

Would like std >> what’s being measured

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Grinding – grinding depth

Max amount

6mm 32 13 11

12 mm P-501

Laughlin AFB

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Mortar Rich Surface – P-501 & 32 13 11

Deficient in CA – top 3 mm

No >4.75 mm CA

Hard to detect in operation

Test Method?

Sampling

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Mortar Rich Layer

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Mortar Rich Layer

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Latent Defects

Some defects are not detectable during

construction

Little or no quantitative limits

No test methods

Contractor liability

Absence of standards would seem to be an

owner’s responsibility

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In Summary

P&B of Test Method

Verifiable Specification Limits

New methods anticipating latent defects

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QED

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