Hydration kinetics of fly ash-portland cement paste with low water to cementitious powder ratio

Fly ash is widely used as a supplementary cementitious material in high performance concrete because of its benefits in enhancing both fresh and long-term concrete properties and as it promotes eco-friendly construction. In the past, many investigations have been carried out mainly to elucidate the pozzolanic reaction of fly ash and its effect on the microstructure of the fly ash-cement paste. Although the effect of fly ash on hydration has been established experimentally, the quantitative influence of fly ash on the kinetics of cement hydration is not well understood. In particular, for modern high-performance concretes with low w/b ratios, the effect of the fly ash on the cement hydration may be different. To predict the performance of fly ash concrete accurately throughout its service life, a more quantitative understanding of the effect of fly ash on cement hydration in low w/b ratio cementitious mixtures is needed.