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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
TFHRC Research Team
- Jussara Tanesi, PhD - SES & Associates
- Haejin Kim, PhD - SES & Associates
- Mengesha Beyene, PhD - SES & Associates
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER TURNER-FAIRBANK HIGHWAY - - PowerPoint PPT Presentation
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER TURNER-FAIRBANK HIGHWAY - - PowerPoint PPT Presentation
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER TURNER-FAIRBANK HIGHWAY RESEARCH CENTER TFHRC Research Team Jussara Tanesi, PhD - SES & Associates Haejin Kim, PhD - SES & Associates Mengesha Beyene, PhD - SES & Associates
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Outline
- Project Background
- Why this study?
- What is the problem? What to address!
- Objectives
- Data acquisition/analysis
- Conclusions/future work
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Background
- Durability Issues in Concrete:
– Chemical: ASR, ACR,…... – Physical: Cyclic F-T actions
- Maintaining F-T durability
- Adequate air-void system
– Total air: 5±1 - 8±1 Percent – Specific surface > 600 in-1 – Spacing factor < 0.008 in
Corr et al, 2002
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
IBRC Program: Castlewood Canyon Bridge Rehab Using Shotcrete/CFRP Wrap
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Existing Test Procedures!
- ASTM C231 measures air in fresh concrete, 1949
- C457 measures air system in hardened concrete
– Tedious, time-consuming, labor intensive
- RapidAir 457 (automated)
– Problems: too late addressing inadequacies in SS, SF
- AVA: T 348, very sensitive, high variability
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Objectives
- Examine feasibility of using SAM developed by
OSU in assessing air-void system of fresh concrete
- Today’s presentation: TFHRC’s Concrete lab
experimentation with SAM
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
How SAM Works
1. Step 1: EP @ 14.5 psi 2. Step 2: EP @ 30 psi 3. Step 3: EP @ 45 psi 4. Open petcock 5. Repeat steps 1-3 6. SAM # = difference of 1st and 2nd EP @ 45 psi SAM # ≤ 0.2 psi represents adequate SF & SS
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
10 20 30 40 50
Pressure (psi) Time
Top Chamber, Pc Bottom Chamber, Pa Equilibrium Pressure
SAM Measurements Procedure
SAM #
Ley, et al
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Experimental Design
- 4 sets, 64 mixtures – Type I/II, w/c = 0.40 & 0.45;
slump: 2±1; No SCMs
- Coarse Agg: LS, HALS, GV; max size: #68 & #57
- Fine Agg: natural sand
- AEAs:1natural rosin, 2 synthetic
- WRAs (PC Based)
- Total air: 3±1-7±1
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Mix Design
Set Coarse Aggregate Weight Cement Water w/c Fine aggregate Air Entraining Water Reducer Type A,F Type lb/yd3 lb/yd3 lb/yd3 lb/yd3 Type
- z/cwt
- z/cwt
Set 1 Limestone LS 1846 611 275 0.45 1034-1305 natural rosin 0.15-1.20
- 1084-1303
synthetic_1 0.06-1.21
- Set 2
Limestone LS 1848 611 244 0.40 1251-1361 natural rosin 0.02-0.79 2.1-4.5 1210-1364 synthetic_2 0.01-0.31 2.1-4.3 Set 3 Gravel GL 1752 611 244 0.40 1166-1364 natural rosin 0.01-0.75 1.1-3.2 1166-1364 synthetic_2 0.02-0.21 1.1-2.7 Set 4 High abs. limestone HALS 1758 611 244 0.40 1210-1364 natural rosin 0.02-0.70 1.3-8.0 1254-1364 synthetic_2 0.01-0.11 7.7-8.1
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Fresh Concrete Properties
Mix ID Slump (in.) Unit Wt. (lbs/ft3) Fresh Air (%) C231 Gravimet ric Air (%) C138 SAM#3P (psi)
Control
45LS-1 1.00 148.9 2.3 2.4 0.40
Set 1 - Synthetic_1 AEA
45LS-S1-2 1.50 148.0 2.7 2.8 0.57 45LS-S1-3 0.75 148.6 2.9 2.6 0.74 45LS-S1-4 2.00 146.6 3.7 3.6 0.22 45LS-S1-5 1.75 146.5 4.2 4.0 0.21 45LS-S1-6 1.75 145.2 4.6 4.7 0.24 45LS-S1-7 2.50 143.7 5.4 5.3 0.17 45LS-S1-8 3.00 141.8 6.4 6.5 0.18 45LS-S1-9 3.00 140.2 7.2 7.5 0.16
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Hardened Concrete Properties
Set 4 Mix ID 28-day Strength (psi) Hardened air void parameters Air content (%) Specific surface (in-1)
Recommended ACI > 600 in-1
Spacing factor (in)
Recommended ACI: < 0.008 in
40HALS-7
8349 2.8 238 0.0259
40HALS-NR-2
8458 2.8 499 0.0124
40HALS-NR-3
8265 3.2 315 0.0184
40HALS-NR-1
8539 3.5 392 0.0144
40HALS-NR-4
8586 3.7 376 0.0144
40HALS-NR-5
8134 3.6 520 0.0105
40HALS-NR-6
7408 5.7 785 0.0057
40HALS-NR-8
5505 4.6 547 0.0090
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Relation Between SAM & Fresh/Hardened Air Content
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
SAM vs. Spacing Factor
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0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Spacing Factor (in) SAM Number (psi) Lab Data OSU Field Data LAB Data FHWA ACI 201.2R
Ley, et al
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SAM vs. Specific Surface
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Spacing Factor & Fresh Air content
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
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% Spacing Factor (in) Air Content of Concrete (Pressure)
No Polycarboxylate Polycarboxylate Freeman et al., 2012
Open symbols failed ASTM C666
No! Yes!
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Conclusions
- SAM is Similar to ASTM C231, inexpensive, easy to
conduct , fast
- SAM # of 0.20 is relatively a good indicator of
adequate SF/SS
- In this study a 4% air content also showed a good
correlation with SF and SS
- Accuracy 85-90 percent
- State DOTs are interested in SAM (QA tool)
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
Future work
- Submitted to AASHTO as TP
- Conduct a comprehensive round-robin study
- Any future study should include SCMs
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TURNER-FAIRBANK HIGHWAY RESEARCH CENTER