New insights into the role of fly ash in mitigating alkali-silica reaction (ASR) in concrete

Journal Article · Tue Jun 15 04:00:00 EDT 2021 · Cement and Concrete Research

DOI:https://doi.org/10.1016/J.CEMCONRES.2021.106440· OSTI ID:23206282

Hay, Rotana; Ostertag, Claudia P. ^[1]

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1. Department of Civil and Environmental Engineering, University of California, Berkeley, CA, 94720 (United States)

Alkali-silica reaction (ASR) mitigation mechanisms of fly ash in concrete are still being debated and remain an interesting research topic. This study provides new insights into the role of aluminum oxide (Al{sub 2}O{sub 3}) in fly ash particles on ASR mitigation. A comprehensive test program was conducted and included expansion measurements, dissolution model experiments of exposed and embedded borosilicate glass elements, analyses of pore and immersion solutions, quantification of Ca(OH){sub 2} content, and microstructural analyses. It was found that in addition to the traditionally accepted mitigation mechanisms such as alkali binding, diffusion control and reduction in available Ca(OH){sub 2}, dissolution control of reactive aggregates by aluminum discharged from fly ash particles also contributed to the ASR mitigation. Re-introducing alkalis to fly ash-incorporated concrete prisms which exhibited undeleterious expansion under a long-term ASR exposure triggered and significantly increased the subsequent expansion.

• OSTI ID: 23206282
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 144; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
ALUMINIUM OXIDES
BOROSILICATE GLASS
CALCIUM HYDROXIDES
CONCRETES
DIFFUSION
DISSOLUTION
FLY ASH
MICROSTRUCTURE
PARTICLES
SILICA
SOLUTIONS