Effect of glass powder on alkali-silica reaction mitigation for tunnel waste rock slag in concrete

Alkali-silica reaction (ASR) poses a critical damage to concrete structures, which will lead to a serious reduction for the service life of concrete. This study investigated the mitigation of ASR using glass powder (GP) through accelerated mortar bar tests (AMBT), with fly ash (FA) and ground granulated blast-furnace slag (GGBS) setting as control groups, and the replacement ratio of GP, FA and GGBS is 0, 5 %, 10 %, 20 %, 30 % and 40 % respectively. The results reveal that both FA and GGBS can mitigate the possibility of ASR: GGBS can significantly mitigate ASR only when its content reaches up to 40 % and FA effectively suppressed ASR with a dosage of 20 %. For the GP, particles larger than 75 μm will increase the risk of ASR, and as evidenced by the clear presence of ASR-gel and cracks in the mortar bars observed. Conversely, GP with particle sizes smaller than 75 μm effectively mitigated ASR, achieving significant suppression at a content of 20 %. The possible mitigation mechanism of GP could be attributed to the pozzolanic reaction between the GP and the alkali in the concrete, which reduces the alkali in the cement. This work might offer some reference to ASR risk control in concrete.