低温下不同粉煤灰掺量对水泥水化影响的试验研究

An Experimental Study of the Influence of Different Dosage Fly Ash on Cement Hydration in Low Temperatures

为了从根本上了解低温条件下混凝土内部结构的形成进程和强度增长规律,解决寒冷地区混凝土冻害问题,根据GB/T12959—2008《水泥水化热测定方法》中的直接法研究了相同恒定低温环境下掺粉煤灰和不掺粉煤灰的水泥浆体的水化程度,比较了各配合比下水化热的变化规律.试验结果表明:水泥被部分粉煤灰替代后,水化热相比于纯水泥水化热有所降低,但降低的幅度与粉煤灰的替代量不成正比;掺入粉煤灰后,对前期水化热降低比较大,对后期水化热降低较小.

In order to learn the internal structure of concrete and the growth law of cement strength under low temperature to solve the freezing problems in cold regions, the variation of heat hydration in different mix was compared based on the direct method mentioned in GB/T12959-2008“Determination of Cement Heat Hydration”to study the degree of hydration of cement paste with and without fly ash under the same constant low temperature condition. The experimental results show that due to the replacement of a part of cement with fly ash, the heat hydration of cementitious material decreased when compared with the heat hydration of pure cement. However, there is no proportional relationship between the reduced magnitude and the replaced quantity of fly ash. With the mixtur of fly ash, there is a significant effect on lowering the heat of hydration in early stage but the influence is weak in late stage.