Thesis
Evaluation of recycled concrete aggregate produced from demolished runway panels as a substitute for coarse aggregates in new Portland cement pavements
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/102407
Abstract
The goals of this study were to investigate the effects of substituting recycled concrete aggregate (RCA) for natural aggregate (NA) in concrete intended for new portland cement concrete pavements (PCCP), and to investigate the effects of substituting fly ash for portland cement while simultaneously substituting RCA for NA. The RCA investigated in this study was produced from demolished runway panels at Fairchild Air Force Base in eastern Washington. Eight concrete mixes were prepared in this study, based on the same reference mix design, which incorporated different amounts of RCA as a substitute for coarse aggregate (0%, 15%, 30% and 45%) and fly ash as a substitute for portland cement (0% and 20%). The slump, air content and density of the fresh concrete were determined. Cylinder and beam specimens from each of the eight mixes were tested to investigate the effects of RCA and fly ash on the hardened concrete properties, including compressive strength, modulus of rupture (MOR), coefficient of thermal expansion (CTE) and drying shrinkage. Properties of the RCA were also v determined, including specific gravity, absorption, Los Angeles abrasion loss, degradation, and alkali-silica reactivity (ASR). It is recommended that the RCA be washed and any fine materials removed prior to use to meet the Washington State Department of Transportation (WSDOT) degradation requirement. The RCA used in this study did show signs of being alkali-silica reactive, but further tests are needed to confirm that this expansion is due to the alkali-silica reaction. If the RCA is confirmed to be reactive, this situation can be mitigated through the use of low-alkali cement or fly ash substitution. It was found that fresh concrete density decreased with the addition of RCA. Substituting RCA for coarse aggregate at rates up to 45% was found to have no statisticallysignificant effects on compressive strength, MOR, and CTE values. It is recommended that additional research be conducted with RCA substitution rates greater than 45%. Based on the results of this study, the use of RCA as a substitute for natural coarse aggregate seems promising for use in new PCCP in Washington State
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Details
- Title
- Evaluation of recycled concrete aggregate produced from demolished runway panels as a substitute for coarse aggregates in new Portland cement pavements
- Creators
- Timothy Charles Spry
- Contributors
- David McLean (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525132401842
- Language
- English
- Resource Type
- Thesis