早龄期混凝土高温-再养护后的抗压性能

Mechanical properties of early age concrete after high temperature re-curing

为了研究早龄期混凝土遭受高温再养护后的抗压性能,对混凝土试块设置不同的高温龄期(7、14、21、28 d)、高温温度(100、300、500℃)和高温后的再养护时间(再养护28 d、再养护56 d),并进行了加载试验,分析了高温龄期、温度及高温后再养护时间对混凝土抗压性能的影响。结果表明:混凝土高温龄期较早(≤14 d),遭受温度较低(100℃)时,温度促进了混凝土的水化,其抗压强度有所提高。但高温龄期较晚(21~28 d)时,混凝土的抗压强度随温度升高而降低。相同温度时,早龄期混凝土高温-再养护至28 d的抗压强度低于28 d龄期高温后的强度。早龄期高温-再养护混凝土的抗压强度随再养护时间的增长有所增加,但增加幅度趋缓。

In order to study the compressive properties of early age concrete subjected to high-temperature re-curing,different high-temperature ages(7,14,21,28 d),high-temperature temperatures(100℃,300℃,500℃)and re-curing time after high temperature(28,56 d)were set for concrete test blocks,and loading tests were carried out.The effects of high temperature age,temperature and re-curing time after high temperature on the compressive properties of concrete were analyzed.The results show that when the high temperature age of the concrete is earlier than 14 days and the temperature is lower(100℃),the temperature promotes the hydration of the concrete and the compressive strength of the concrete is improved.However,when the high-temperature age is later(21~28 d),the compressive strength of concrete decreases with the increase of temperature.The compressive strength of early-age concrete after high temperature re-curing to 28 d is lower than that after 28 d subjected to the same temperature.The compressive strength of early age concrete after high temperature re-curing increases with the increase of re-curing time,but the increase rate slows down.