Mechanistic Role of Supplementary Cementitious Materials (SCMs) in Alkali-Silica Reaction (ASR) Mitigation

Author: Tapas, M. J., Vessalas, K., Thomas, P., Sirivivatnanon, V., Kidd, P.
Type: Conference Paper, Concrete 2019, Sydney Australia.
Date: 2019.

Keywords: Alkali-silica reaction; Supplementary cementitious materials; Fly ash; Slag.

Abstract: Alkali-silica reaction (ASR) can cause premature failure of concrete structures and therefore is a major concrete durability issue. The use of commonly available supplementary cementitious materials (SCMs) such as fly ash and slag is generally regarded as the most optimal and economical solution in mitigating ASR. However, the eminent closure of coal fired power stations in favour of greener technologies for producing energy and increasing demand in steel recycling threaten the future supply of SCMs that are currently available. Hence, the need to better understand the ASR mitigation process in order to be able to identify potential alternatives. This experimental study aims to provide a better understanding of ASR mitigation by studying the influence of various SCMs on ASR expansion, portlandite consumption and pore solution alkalinity. Results show that the efficacy of the SCMs in reducing ASR expansion can be correlated to their ability to consume portlandite and bind alkalis. Further, results suggest that any material that has high content of soluble AI2O3 and/or SiO2M is a potential SCM for ASR mitigation.