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 Outline • Project Background Why this study? What is the problem? What to address! • Objectives • Data acquisition/analysis • Conclusions/future work
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
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER IBRC Program: Castlewood Canyon Bridge Rehab Using Shotcrete/CFRP Wrap
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER
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
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
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 1 st and 2 nd EP @ 45 psi SAM # ≤ 0.2 psi represents adequate SF & SS
SAM Measurements Procedure TURNER-FAIRBANK HIGHWAY RESEARCH CENTER 50 40 SAM # Pressure (psi) 30 20 Top Chamber, Pc 10 Bottom Chamber, Pa Equilibrium Pressure 0 Time Ley, et al
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
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Mix Design Water Coarse Fine Reducer Cement Water Air Entraining Weight Aggregate aggregate Set w/c Type A,F Type lb/yd 3 lb/yd 3 lb/yd 3 lb/yd 3 Type oz/cwt oz/cwt 1034-1305 natural rosin 0.15-1.20 - Limestone Set 1 1846 611 275 0.45 LS 1084-1303 synthetic_1 0.06-1.21 - 1251-1361 natural rosin 0.02-0.79 2.1-4.5 Limestone Set 2 1848 611 244 0.40 LS 1210-1364 synthetic_2 0.01-0.31 2.1-4.3 1166-1364 natural rosin 0.01-0.75 1.1-3.2 Gravel Set 3 1752 611 244 0.40 GL 1166-1364 synthetic_2 0.02-0.21 1.1-2.7 1210-1364 natural rosin 0.02-0.70 1.3-8.0 High abs. limestone Set 4 1758 611 244 0.40 1254-1364 synthetic_2 0.01-0.11 7.7-8.1 HALS
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Fresh Concrete Properties Gravimet Slump Unit Wt. Fresh Air SAM#3P Mix ID ric Air (in.) (lbs/ft3) (%) C231 (psi) (%) C138 45LS-1 1.00 148.9 2.3 2.4 0.40 Control 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 Set 1 - Synthetic_1 AEA 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
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Hardened Concrete Properties Hardened air void parameters Specific surface Spacing (in -1 ) factor (in) Air content Recommended (%) Recommended 28-day ACI > 600 in -1 ACI: < 0.008 in Set 4 Mix ID Strength (psi) 8349 2.8 238 0.0259 40HALS-7 8458 2.8 499 0.0124 40HALS-NR-2 8265 3.2 315 0.0184 40HALS-NR-3 8539 3.5 392 0.0144 40HALS-NR-1 8586 3.7 376 0.0144 40HALS-NR-4 8134 3.6 520 0.0105 40HALS-NR-5 7408 5.7 785 0.0057 40HALS-NR-6 5505 4.6 547 0.0090 40HALS-NR-8
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Relation Between SAM & Fresh/Hardened Air Content
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER SAM vs. Spacing Factor
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER 0.02 0.018 0.016 0.014 Spacing Factor (in) 0.012 0.01 0.008 ACI 201.2R 0.006 0.004 Lab Data OSU Field Data 0.002 LAB Data FHWA 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 SAM Number (psi) Ley, et al
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER SAM vs. Specific Surface
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Spacing Factor & Fresh Air content
0.024 TURNER-FAIRBANK HIGHWAY RESEARCH CENTER 0.022 No Polycarboxylate 0.020 Polycarboxylate Spacing Factor (in) 0.018 Open symbols 0.016 failed ASTM C666 0.014 No! 0.012 0.010 0.008 Yes! 0.006 0.004 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% Air Content of Concrete (Pressure) Freeman et al., 2012
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)
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Future work • Submitted to AASHTO as TP • Conduct a comprehensive round-robin study • Any future study should include SCMs
TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Questions! http://www.superairmeter.com/
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