自密实混凝土绝热温升速率试验研究

Experimental study of adiabatic temperature rise rate of self-compacting concrete

通过绝热温升试验研究入模温度和配合比参数,包括粉煤灰掺量、粉煤灰和矿渣复掺、水胶(灰)比等对自密实混凝土绝热温升速率的影响.通过基于等效时间的绝热温升速率曲线特征,分析各配合比参数对温升速率特征值的影响.结果表明:(入模)温度对试验配合比绝热温升的影响可以用Arrhenius方程进行描述;水泥用量和水灰比对温升速率的影响最为显著;温升速率峰值与单方混凝土水泥用量存在较明显的正相关关系,且随着水灰比的增大明显降低;各配合比的诱导期时间、温升速率加速期持续时间相差不大,减速期持续时间相差较为悬殊;粉煤灰或矿渣替代水泥,导致温升速率峰值降低,减速期明显延长.

Effects of initial temperature and mixture design parameters on self-compacting concrete adiabatic temperature rise are experimentally examined.The mix design parameters include dosage of fly ash and slag,water to binder ratio,water to cement ratio etc.Correlations between mixture design parameters and equivalent age adiabatic temperature rise rate are discussed.The results show that：The effects of temperature on the adiabatic temperature rise rate can be described by Arrhenius equation.The amount of cement and water-cement ratio affects the temperature rise rate most significantly among all the mix design parameters.An obvious positive correlation exists between the peak of temperature rise rate and cement dosage per cubic meter concrete,and the temperature rise rate decreased with the increase of water-cement ratio obviously.For each mix proportion,in terms of time process,the induction period and temperature rise rate acceleration period duration are similar,but the deceleration period duration are less disparity.Replacement of cement with fly ash or slag makes the peak of temperature rise rate reduced;and the deceleration period extended obviously.