PCC properties to support w/c determination for durability.

Details

• Creators:
  Yohannes, Yohannes ; Olek, Jan
• Corporate Creators:
  Purdue University. Joint Transportation Research Program
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Water cement ratio
  • Concrete mixing
  • Evaluation and assessment
  • Field tests
  • Laboratory tests
  • Weight
  • Concrete--Moisture--Measurement
  • Pavements, Concrete--Testing
• Publication/ Report Number:
  FHWA/IN/JTRP-2012/24
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report.
• Corporate Publisher:
  Indiana Department of Transportation
• Abstract:
  The fresh concrete water‐cement ratio (w/c) determination tool is urgently needed for use in the QC/QA process at the job site. Various ; techniques have been used in the past to determine this parameter. However, many of these techniques can be complicated and time ; consuming. Furthermore, the extensive calibration is often needed to correlate the properties measured by these techniques with w/c. ; During the course of the present study, the method for the use of the unit weight for the determination of w/c of fresh concrete has ; been developed and evaluated on both laboratory and field concretes. Additionally, the accuracy of using microwave oven technique ; for w/c determination reported by previous research was confirmed. Finally, the accuracies of unit weight and microwave oven ; techniques for the determination of w/c were compared. ; The unit weights required for this method have been determined either by using a “zero‐air” procedure (ZAP) developed as a part of this ; study or by using conventional (following AASHTO specifications) methods. The ZAP technique was used to verify the w/c of 58 different ; laboratory concrete mixes. These verification efforts revealed that the minimum, maximum, standard error, and 95th percentile of the ; differences (Δw/c) between batched and determined w/c were, respectively, 0.000, 0.042, 0.017, and 0.030. The AASHTO determined ; unit weight (which also required measurements of the actual air content of concrete) was used to verify the w/c values of additional set ; of 57 laboratory mixes. When using the AASHTO unit weights (and air contents) the minimum, maximum, standard error, and 95th ; percentile of Δw/c of were, respectively, 0.000, 0.075, 0.030, and 0.054. In addition, the AASHTO unit weight method was also used to ; verify the w/c values of 22 different field mixtures. For this case, the differences (Δw/c) between the design and unit weight‐calculated ; values of w/c were in the range ±0.030 for all but one mixture. Finally, direct comparison of the results from the proposed method with ; the results obtained from the microwave oven method revealed that the former is faster but slightly less accurate. Specifically, when ; used on five separate concrete samples, the accuracy of the microwave oven method was 0.010, much smaller than previously ; mentioned values of 0.030 (for the ZAP) and 0.054 (for the AASHTO) unit weight methods.
  More +
• Format:
  PDF
• Funding:
  SPR-3201
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25472/dot_25472_DS1.pdf
• File Type:
  [PDF - 2.04 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:9ef0251d557937cc6cadd5aab588a4794b646395436a67a36ae302149e33e91d36c46514d3078e320a91382c503983c5e9cebfcd1605c74499011322655ec723