New Performance Approach to Evaluate ASR in Concrete

Study objectives are to evaluate a wide selection of concrete mix designs to validate the use of the new AASHTO TP-144-21 (T-FAST) and alkali threshold test (ATT) methods in conjunction with mix design data, cement mill reports and SCM properties to determine the likelihood of alkali-silica reaction (ASR) gel formation in concrete. The formation of ASR gels in concrete has been a major issue for the industry since they were first discovered in the 1930s. The gels are formed by the reaction of the alkalis from the cement with the silica in certain ASR susceptible aggregates. The gels can absorb water, swell, and cause the concrete to crack. The first tests to determine the ASR susceptibility of aggregates came out in 1947. There have been many tests since then. They mostly rely on the measurement of engineering properties. Typically, a sample of mortar or aggregate is immersed in sodium hydroxide solution at elevated temperature and the physical expansion of the sample measured after a period. The T-FAST method is a more sensitive and accurate test which predicts ASR expansion using purely chemical measurements. The test is completed in 21 days. Although these tests can detect ASR reactive sites in aggregates, they cannot determine whether gels will form in the resulting concrete. That depends on the alkali loading of the mix. The idea of measuring the alkali threshold of aggregates has been discussed for many years although no simple or reliable test has been available. A new test, (ATT) has been developed in the chemistry laboratory at the Turner Fairbank Highway Research Center (TFHRC). The test is simple and is completed in 21 days. With the ATT method it is possible to determine the likelihood of ASR formation in concrete. While research at TFHRC supports this notion there is a need to verify the validity of this technique by evaluating many commonly used aggregates. Partners in this pooled fund study will select concrete mix designs with known ASR field performance either positive or negative. They will supply samples of concrete mixtures components including aggregates, cements, and SCMs along with the corresponding mix designs to TFHRC where the chemistry laboratory will use the T-FAST and ATT methods to evaluate their ASR reactivity and the alkali threshold of the aggregate combination. This information will be compared against the alkali loading of the provided mixes to ensure that the T-FAST/ATT combination would have predicted field performance. Further, these results will be used to design an ASR mitigation test like T-FAST.

• Record URL:
  http://www.pooledfund.org/Details/Study/753

Language

• English

Project

• Status: Programmed
• Funding: $305000
• Contract Numbers:

  TPF-5(521)

• Sponsor Organizations:

  Colorado Department of Transportation

  2829 W. Howard Place
  Denver, CO  United States  80204

  California Department of Transportation

  1227 O Street
  Sacramento, CA  United States  95814

  Connecticut Department of Transportation

  2800 Berlin Turnpike
  P. O. Box 317546
  Newington, CT  United States  06131-7546

  Georgia Department of Transportation

  600 West Peachtree St
  Atlanta, GA  United States  30308

  Idaho Department of Transportation

  P.O. Box 7129
  3311 W. State Street
  Boise, ID  United States  83707-1129

  Kansas Department of Transportation

  Eisenhower State Office Building
  700 SW Harrison Street
  Topeka, KS  United States  66603-3754

  South Dakota Department of Transportation

  700 East Broadway Avenue
  Pierre, SD  United States  57501

  Texas Department of Transportation

  125 E. 11th Street
  Austin, TX  United States  78701-2483

  Delaware Department of Transportation

  800 S Bay Road
  P.O. Box 778
  Dover, DE  United States  19903

  Alaska Department of Transportation

  ,    
• Project Managers:

  Arnold, Terry

• Start Date: 20240426
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Alkali silica reactions; Concrete; Cracking of concrete pavements; Gels; Materials tests; Mix design; Performance tests; Swelling; Test procedures
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01888232
• Record Type: Research project
• Source Agency: Federal Highway Administration
• Contract Numbers: TPF-5(521)
• Files: RIP, USDOT
• Created Date: Jul 20 2023 4:32PM