Microsilica and ground granulated blast furnace slag effects on hydration temperature

The heat of hydration of cement mixes is of great importance to civil engineers. A testing setup was developed to provide a continuous recording of temperature inside cement mixes by means of a computer, digital voltmeter, and thermo-couples. Four mixes were tested by the suggested testing setup. A plain normal Portland cement (NPC), 90% NPC/10% microsilica, 40% NPC/ 10% microsilica/50% ground granulated blast furnace slag (ggbs), and 50% NPC/50% sand mixes were used. Microsilica reduced the temperature rise in paste and ggbs reduced it even further. Cement content was seen, as expected, to have significant effect on the rise in hydration temperature. Cement replacement materials had also clear effect on the time needed to reach the peak temperature. Microsilica slightly accelerated the arrival time at peak temperature, whereas ggbs significantly delayed it. Moreover, ggbs clearly reduced the differential change in temperature as a function of time compared to the other mixes.