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Standards for Concrete
Materials & Portland
Cement Concrete PavingWhat they do and don’t tell us
September 2015
www.CTLGroup.com
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
3
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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
4
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
5
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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
6
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What Makes a Good Standard
Specifications
Clearly defined requirements
Quantifiable
Verifiable
Relevant
Test Methods
Relevant
Precision and bias
Economically manageable
7
A few general topics
8
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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
9
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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
10
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Origin of Specification Limits
Laboratory research
Accumulated Experience
Field Service Record
Crony capitalism
11
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Field Service Records – Gold Standard
12
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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
14
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Variation
15
100mean
stdCV
Standard deviation from mean
Mean
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False Rejection
16
standard deviation from mean
pro
babili
ty o
f occurr
ence
Max limit
P(false rejection)
True Value
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False Pass
17
standard deviation from mean
pro
babili
ty o
f occurr
ence
Max limit True Value
P(false pass)
Materials
18
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Materials Standards Relevant to PCCP
Cement
SCM’s
Aggregates
Curing materials
19
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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)
23
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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
24
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Coal Fly Ash
Class C –
Lots of personality
Setting, workability
durability
Class F –
Little personality
Variability
25
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
26
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Quarry Variability
d27
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AAR
Brief history
Current guidance
ASTM C1778
AASHTO PP65
Problems yet
28
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Durability of Aggregate D-Cracking
ASTM Method C666
P&B
Good concept
Marginal
Economically
30
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Aggregate Durability - Popouts
31
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Aggregate Durability – Surface Damage
UFGS 32 13 11
≤1% total del.mtls.
Clearly described
Long Test Method
Marginal economically
32
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Curing Compounds (ASTM C 156)
Clever test concept
P&B !!!!
Limit = 0.55 kg/m2
Std = 0.30 kg/m2
33
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Evaporation Reducers
No specs
No test methods
Testimonials on field performance
34
Construction Specifications
35
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Some Problem Properties
Strength
Consolidation
Curing
Edge slump
Excess surface
mortar
Plastic Shrinkage
Grinding
Latent defects
36
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Strength - ASTM C78 (1930)
37
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
38
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Types of Poor Consolidation
39
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Types of Poor Consolidation
40
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P C601 Test Method – C642
Mass air (Ma)
Mass water (Mw)
Ma– Mw = volume (V)
Density = Ma/V
41
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Plastic Shrinkage Cracking
42
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Plastic Shrinkage Cracking
Evaporation > Bleeding
ACI 305R
Critical evaporation
threshold: 0.2 lb/ft2/h
Based on old concrete
technology
43
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Curing Compound Application
44
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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.
45
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Early Curing Compound Application
46
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Measuring Edge Slump
47
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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
48
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Grinding – grinding depth
Max amount
6mm 32 13 11
12 mm P-501
Laughlin AFB
49
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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
50
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Mortar Rich Layer
51
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Mortar Rich Layer
52
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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
53
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In Summary
P&B of Test Method
Verifiable Specification Limits
New methods anticipating latent defects
54
QED
55
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