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SAM Concrete TestingThe path to better concrete
acceptance testing
PowerPoint Provided by: Tyler Ley, PE, PhD
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Dan DeGraaf, P.E. Michigan Concrete Association
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What is the dream?
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What is the dream?
Concrete that is economical, consistent, and long lasting with
minimal maintenance.
Why are we talking about this?
• The heart of the PEM effort is early age test methods to predict the long term performance of concrete.
• If we don’t try to implement these tests then nothing will change.
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What gets measured gets managed.
- Peter Drucker
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When was the last time that we did this?
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When was the last time that we did this?
• Air meter (Klein and Walker, 1949)
68 years
• Rapid Chloride Permeability Test (Whiting, 1981)
36 years
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Why should I do this?
Does the test measure something I care about?
Do my current tests tell me everything I need to know?
Do I have the resources to make changes?
Does this fit into my priorities?
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Are you sure?
What are your steps to implement?
Convince yourself
Convince others
Try the test
Shadow specification
Specification on a few projects
Daily practice
Set a goal and get started.
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What are your steps to implement?
Convince yourself
Convince others
Try the test
Shadow specification
Specification on a few projects
Daily practice
Set a goal and get started.
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Ask questions
Communicate what you are finding
Find out what works for you
What are your steps to implement?
Convince yourself
Convince others
Try the test
Shadow specification
Specification on a few projects
Daily practice
Set a goal and get started.
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Ask questions
Communicate what you are finding
Find out what works for you
Set a goal and get started.
What are our steps to implement?
Establish that the test meets a need and is useful
Standardize the test
Find critical performance limits
Establish test variability
Recommend a specification
Make changes based on comments
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Super Air Meter (AASHTO TP 118)
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• Volume of air provided is the same for both.
• Case B has a better air void distribution.
A B
What Do You Want in an Air-Void System?
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0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0 2 4 6 8 10 12
AST
M C
45
7 S
pac
ing
Fact
or,
in
Air %
WROS .45
WROS .45 + PC1
ACI 201.2R
You can’t tell the size of the
bubbles by looking at the volume!!!
Small
bubbles
Large
bubbles
Yes!
No!
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
0.022
0.024
2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0%
Sp
acin
g F
acto
r (
in)
Air Content of Concrete (Pressure)
No Polycarboxylate
Polycarboxylate
Open symbols
failed ASTM
C666
Freeman et al., 2012
Mixtures with
large bubbles
Yes!
No!
Ley et al., 2017
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Spac
ing
Fact
or
(in
che
s)
SAM Number
WROS .40WROS + PC1 .40
ACI 201.2R
Recommended
Not Recommended
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8
Du
rab
ility
Fac
tor
Fresh Air %
WROS .40 WROS + PC1 .40
Recommended
Not Recommended
Ley et al., 2017
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0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Du
rab
ility
Fac
tor
SAM Number
WROS .40WROS + PC1 .40
Recommended
Not Recommended
Ley et al., 2017
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.00 0.10 0.20 0.30 0.40 0.50 0.60
Du
rab
ility
Fac
tor
SAM Number
WROS .45
WROS .40
WROS + WR .40
WROS + PC1 .40
WROS + PC1 .35
WROS + PC2 .40
WROS + PC3 .40
WROS + PC4 .40
WROS + PC5 .40
Recommended
Not Recommended
68 mixtures show a 88% agreement.
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Cliff of Doom
Over 227 lab mixtures from two different research groups88% agreement
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Ley et al., 2017
0.008” spacing factor
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80
Spac
ing
Fact
or
(in
)
SAM Number
AET MnDOT
CODOT
FHWA
GEIGER
IOWA
Kansas
MICHIGAN
MIT
N. DAKOTA
ODOT
PennDOT
UDOT
WisDOT
NO
YES!
13 DOTs over 270 field mixtures81% agreement
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Discussion
The SAM Number correlates to performance in rapid freeze thaw testing.
A SAM Number of 0.20 correlates to a spacing factor of 0.008” for 497concrete mixtures completed by 13 different DOTs and two research groups.
88% agreement in lab
81% agreement in the field
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0
10
20
30
40
50
Pre
ssu
re (
psi)
Time
Top Chamber, Pc
Bottom Chamber, Pa
Equilibrium Pressure
SAM
number
Air content and SAM number given here
Atmospheric
Pressure
35 psi other pressures
not shown
Returned to
Atmospheric
Pressure
High spacing
factorLow spacing
factor
How is this useful???
• If you have a high spacing factor (bubbles far apart) then pressure step 1 will cause the bubbles to dissolve
• When we apply pressure step 2 there will be a large difference in how the concrete responds to pressure.
• This will cause a high SAM number.
How is this useful???
• If you have a low spacing factor (bubbles close together) then pressure step 1 will not dissolve many bubbles
• When we apply pressure step 2 there will be a small difference between the two pressure curves.
• This will cause a low SAM number.
Discussion
The SAM Number tells you about the bubble size distribution in fresh concrete and the total air does not do this.
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Test Method Parameter COV
Time to
complete the
test
SAM SAM Number1 15.2% 10 min
ASTM C457 Spacing Factor2
20.1% 7 days
ASTM C666 Durability Factor3
22.7% 3.5 months
1Assumes a SAM Number of 0.32 and a standard deviation of 0.049 from this paper
2From ASTM C457
3From ASTM C666 with a durability factor of 75 and Method B170 SAM comparisons were used to determine this.
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How variable is the test?
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One standard deviation
Two standard deviations
high low high low
Compressive strength (psi) 5000 5500 4500 6000 4000
Air meter (%) 6 6.4 5.6 6.8 5.2
SAM 0.20 0.23 0.17 0.26 0.14
Spacing factor (in) 0.008 0.010 0.006 0.0112 0.0048
Freeze Thaw (DF) 70 86 54 102 38
average value
68% of the data will
be in this range
96% of the data will
be in this range
70
75
80
85
90
95
0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Per
cen
tage
agr
eem
ent
SAM Number
Durability Factor 70
34
60
65
70
75
80
85
90
0.1 0.15 0.2 0.25 0.3 0.35
Pe
rcen
t ag
reem
en
t
SAM Number
spacing factor = 0.008"
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Ley et al., 2017
Daily Meter Check
• Pressure chamber to 45 PSI and hold it.
• Wait 2 minutes
• Pressure drop should be less than .04 PSI
• If greater – look for leaks
• Biggest issue is cleaning the rim
• 2nd issue is getting all the air bubbles out of the base
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Does anyone enjoy using the syringe in an air test?
What if we used a funnel instead?
Shotgun
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Shotgun
40
Shotgun
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Recommended SAM Specification
SAM Number Action
< 0.25 Accept the concrete
0.25 - 0.30
Increase air content
on next truck, accept
the concrete
> 0.30 Reject the concrete
Air content > 4%
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FieldMixture Design
SAM Number < 0.20Air content > 4%
Discussion
If the producer designs the SAM Number to be at 0.20 at their working air content then they will have < 2% chance of getting a failing test in the field.
By allowing actions at different SAM Numbers then the producer can bring their materials back within specification before getting them rejected.
The rejection limit is determined by freeze thaw testing (ASTM C 666).
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All our dreams can come true if we have the courage to pursue them.Walt Disney
Set a goal and get started.
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“Super Air Meter”in Michigan
Introduction of SAM to MDOT,Multi-State Pooled-Fund Projects• 2014: MDOT along with 17 other state DOTs: “Improving Specifications to Resist Frost Damage in
Modern Concrete Mixtures”, TPF-5(297). Completion date: 2019• Lead state – Oklahoma DOT• This pooled fund initiative is focused on the development of the SAM• Acquired 2 SAMs for multi-state data gathering and system refinement
• 2017: MDOT along with 12 other states and the FHWA: “Performance Engineered Concrete Paving Mixtures”, TPF-5(368). Completion date: 2021
• Lead state – Iowa DOT• The National Concrete Consortium (NCC) will be the anchor organization for dissemination of research and
outreach for this project (32 dots, industry, academia)• This pooled fund initiative is to develop guidance for the next-generation of performance-based concrete
paving specifications…implement what we know, monitor, measure, and spec refinement• Included in this project will be further study of the SAM and its associated AASHTO provisional test method
• These pooled-fund efforts will greatly aide toward developing Michigan-based specifications for incorporation of the SAM into the MDOT concrete acceptance program
Super Air Meter in Michigan
• FHWA Sponsored State Transportation Innovation Council (STIC)
• STIC Application• September 2016
• SAM Acquisition
• Training, Spec Development, Outreach
STIC Activities, to date
• Spring 2017• Purchased 8 SAMs – total 10
• Summer 2017• Brought Dr. Ley in for a Joint MDOT/MCA training/certification course
• MCA hosted day-long event (classroom and practical laboratory setting) - 30 attendees• MDOT technicians – 12• MDOT Supervisors – 3• Wayne County Road Commission – 1• Contractors – 2• Concrete Suppliers – 1• Consultants – 6• MCA Staff – 5
• MDOT provided 10 SAMs
• Six MDOT SAMs sent to Regions for informational gathering and outreach
MDOT Roads Innovation Task Force (RITF)
• SAM will be demonstrated on two concrete paving projects:• 30-year design life (50-year service life): July 2017 project letting. Bay Region, I-69
from I-75 to I-475
• 50-year design life (75-year service life): Spring 2018 project letting. Grand Region, US-131 from 10 Mile Road to 14 mile Road
• QC and QA informational shadow testing via “Special Provision for Durability Based Field Testing”
• SAM
• Surface Resistivity
AASHTO Committee on Materials and PavementsCOMP (formerly Subcommittee on Materials)
• TPF-5(297):“Improving Specifications to Resist Frost Damage in Modern Concrete Mixtures”
• Presented to Technical Section 3b, Fresh Concrete Properties in 2016• Adopted the SAM as a Provisional Standard Test Method (TP-118)
• TPF-5(368): “Performance Engineered Concrete Paving Mixtures”• Presented to Technical Section 3b, Fresh Concrete Properties in 2016• Adopted the PEM as a Provisional Standard Practice (PP-84)
MDOT Moving Forward
• Nationally - Field acceptance using SAM for payment is not quite there…yet
• Currently own 10 SAMs• 2 - pooled-fund project• 8 – STIC grant
• Partner with MCA to incorporate SAM training module into current MCA Level 1 certified concrete technician course – 2018
• Continue active participation in pooled-fund projects:• “Improving Specifications to Resist Frost Damage in Modern Concrete Mixtures”,
TPF-5(297),• “Performance Engineered Concrete Paving Mixtures”, TPF-5(368)
• Pooled-fund activities along with Michigan-based field testing and outreach will steer future MDOT implementation
2017 SAM Field Testing Data
Questions?
General video about measuring air in concrete: https://www.youtube.com/watch?v=gOAft3z9Sa4&list=PLRq6Z9d0kCT_ObxZG5Mh2edgOyirtn0Co&index=6
videos about the theory behind the SAM and how to run it:
http://www.superairmeter.com/videos.html
https://youtu.be/wKtOKg8eQSw
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