Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

摘要

In this paper,effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21 ± 1°C) and low curing temperature(6.5 ± 1°C)was studied.In order to improve the early strength of the concrete in low temperature,the early strength agent calcium nitrite was added into.Test results indicated that 0.5％ dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent,but 1％ and 2％ dosage of nano-CaCO3 could improve the strength of the concrete by 13％ and 18％ in standard curing temperature and by 17％ and 14％ in low curing temperature at the age of 3days.According to the XRD spectrum,with the dosage up to 1％ to 2％,nano-CaCO3 can change the orientation index significantly,leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.