Effects of curing regimes on strength development of high-strength concrete

The effect of three curing regimes of standard condition (20℃, relative humidity≥90%), elevated temperature of 50℃ and temperature match condition on compressive strength development of high-strength concrete. Results show that elevating curing temperature higher than 50℃ can significantly increase the activity of composite binders consisting of cement-ground granular blast furnace slag (GGBS) and cement-fly ash-silica fume. The compressive strength of concrete prepared with these composite binders and cured at elevated temperature is twice of that cured in the standard condition in 3 d age and continues to grow in long age. The elevated temperature curing regime restrains the compressive strength development of concrete prepared with only Portland cement in long age. Strength of concrete increases greatly when the hydration of binder goes intensively in the stage of nucleation and crystal growth or interaction at phase boundaries. The increasing extent for strength of concrete and its difference among concretes declines when the hydration of binder goes into the stage of diffusion. Concrete prepared with cement-fly ash-silica fume composite binder cured in any regime has the highest strength and the best resistance to chloride ion penetration. This composite binder is suitable for the preparation of high-strength concrete. The strength determined using a sample cured under the standard condition can approximately reflect the property of concrete in real structure for long term. ©, 2015, Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society. All right reserved.