The effect of curing time on the ASR expansion of different HPC composites

HPC composites have been an interesting topic in the field of concrete research over the last few decades. Many fresh and hardened concrete properties have been investigated. However, investigation of early alkali-silica reactions (ASR) in HPC is reported in only a few studies that correlate HPC and ASR expansion. The presence of a different combination of mineral admixtures in HPC is a must. Mineral admixtures such as pulverized fly ash (PFA) and silica fume (SF) have different pozzolanic activities. Therefore, the effect of different early curing regimes on the ASR expansion in HPC composites containing alkali reactive aggregates requires investigation. A total of 25% glass bottle aggregate was found to provide an expansion near that given by most reactive natural aggregates. The effect of curing regime was noticeably different in the control HPC mixture, as cement hydration is highly affected by time. However, in the binary and ternary cementitious HPC composites the performance was found to depend on the constituents forming this composite. The addition of superplasticizer plays an important role in mitigating the ASR expansion. Within the ternary composites, an optimum combination of PFA and SF was found. For the optimum combination, the attractive force among the constituents in the cementitious matrix is maximized. This significant reduction in porosity and total permeability of HPC composites can be utilized to lower the ASR expansion.