三峡三期围堰碾压混凝土中粉煤灰水化热计算研究

Hydration Heat Calculation of Fly Ash in RCC for 3rd Phase Cofferdam of Three Gorges Project

三峡三期围堰碾压混凝土实测温升高,最高温度出现和维持时间长,除其他因素外,还与粉煤灰的水化发热有关。采用分离法计算出碾压混凝土中粉煤灰的水化热,粉煤灰的水化热28 d龄期时约为中热水泥的1/3,150 d时约为1/2。试验研究成果表明:对散热条件较差的大体积碾压混凝土,不容忽视粉煤灰的水化热特别是后期的水化热。

The measured temperature-rise was high and the lasting time of highest temperature was long in the RCC of 3rd phase cofferdam of TGP, which, in addition to other factors, was related to hydration heat of fly ash. A socalled separation method was employed to calculate the hydration heat of fly ash in RCC at ages up to 150 days. The hydration heat of fly ash is about one third of that of moderate heat Portland cement at 28 days and a half of that at 150 days. Considering the modified coefficient using 0.6 water-cement ratio, the heat producting in RCC may be effectively decreased. For massive RCC under bad heat dissipation conditions, the hydration heat of fly ash, especially in the later ages, should not be ignored.