Part II: Durability Assessment of Recycled Concrete Aggregates for use in New Concrete

Jason Ideker, Oregon State University

Co-investigators:

  • Jason H Ideker, Oregon State University
  • Jennifer E. Tanner, University of Wyoming

Summary:

This Phase II investigation into the durability of new concrete incorporating recycled concrete aggregates (RCA) focused on several goals: 1) Provide corroboration of results obtained in Phase I for a multi-laboratory study related to assessing alkali-silica reactivity (ASR) of RCA in accelerated laboratory tests; 2) Investigate the efficacy of mitigation methods to control ASR in concrete containing potentially reactive RCA; 3) Establish long-term data through placement of concrete blocks containing RCA in an outdoor exposure site in Laramie, WY; and 4) Survey state DOTs and other transportation agencies about their perceptions and usage of RCA ASR in concrete within their agency and how that may be improved through the use of a database tracking tool. From Phase II the following main conclusions were drawn: 1) The coefficient of variation limits in ASTM C 1260-07 do not apply to concrete mortar bars incorporating RCA. It is recommended that further testing, using different RCA and more laboratories (at least six), should be completed before a new standard for RCA and/or incorporation of RCA into the current ASTM C 1260 test may be allowed. 2) Generally, as the replacement level of RCA was reduced, the amount of SCM needed to control deleterious ASR also decreased for the RCA sources investigated in this study. 3) Ternary blends containing metakaolin resulted in the most significant decrease in expansions compared to the mixtures with no SCMs. The results of the transportation agency survey showed the following: 1) A vast majority of agencies believed that sustainability was important to their agency and that it was addressed in a clear and meaningful way. 2) A majority, 54%, of agencies believed they had specific guidance for the use of RCA in new concrete; however, only 15% believed that there was strong information from the federal level about the use of RCA in new construction. 3) Of all respondents, 77% indicated their agency was concerned about alkali-silica reaction in concrete in general for their agency. 4) The biggest barriers to using RCA were noted as concerns about quality, a lack of standards and specifications, and unclear guidance on the testing of RCA. 5) The biggest concerns specific to a source of RCA when considering it for use in new construction were increased shrinkage concerns, ASR and residual chlorides. 6) The most sought-after information about a potential RCA source when considering it for use were the existing condition of the RCA when it was taken out of service, the reason it was taken out of service, whether repairs were performed to the structural element taken out of service, and the age of the RCA.

Project Details

Project Type:
Research
Project Status:
Completed
End Date:
February 28,2012
UTC Grant Cycle:
OTREC 2011
UTC Funding:
$103,788
TRB RIP:
26982

Downloadable Products

Other Products

  • Adams, M.P., Gray, B., Ideker, J.H., Tanner, J.E., Jones, A., Fournier, B., Beauchemin, S., Shehata, M., and Johnson, R., “Applicability of Standard Alkali-Silica Reactivity Testing Methods for Recycled Concrete Aggregate In Proceedings of the 12th International Conference on Alkali-Aggregate Reactivity in Concrete, Drimalas, T., Ideker J.H. and Fournier, B. Eds., Austin, Texas, USA, 2012, 10 pp. (PRESENTATION)
  • Alkali-Silica Reactivity of Recycled Concrete Aggregates, Ideker, J.H.,*, Tanner-Eisenhauer, J.E., Adams, M.P. and Joes A., National Concrete Consortium Fall Meeting, September 18, 2012, Seattle, Washington (PRESENTATION)
  • Adams, M.P.* and Ideker, J.H., “Alkali-Silica Reaction in Concrete Made with Recycled Concrete Aggregates,” NRMCA International Concrete Sustainability Conference, May 07-10, 2012, Seattle, Washington (PRESENTATION)
  • Adams, M.P., Gray, B., Ideker, J.H., Fournier, B., Tanner, J.E., Shehata, M., “Applicability of Standard Alkali-Silica Reactivity Testing Methods for Recycled Concrete Aggregate,” The 12th International Conference on Recent Advanced in Concrete Technology and Sustainability Issues, Prague, Czech Republic, October 31st - November 2nd, 2012 (PRESENTATION)