不同龄期混凝土高温后力学性能研究

为研究不同龄期混凝土高温后的力学性能变化，对不同养护龄期的混凝土设置不同的温度和继续养护时间，对其抗压强度和劈裂抗拉强度进行试验。结果表明：各龄期混凝土的抗压强度和劈裂抗拉强度随经历温度的升高基本呈下降趋势，但当温度不高于100 ℃，龄期不大于14 d 时，其强度反而略有上升。混凝土经历相同温度情况下，高温时龄期越早，强度越低。随着高温后继续养护时间的增加，混凝土的强度逐渐恢复，且高温龄期越早，恢复程度越高，但强度恢复增幅逐渐降低。

Study on mechanical properties of concrete at different curing ages and high temperatures

In order to study the variation of mechanical properties of concrete at different curing ages and high temperatures,the compressive strength and splitting tensile strength of concrete at different curing ages were tested by setting different temperatures and continuing curing time.The test results show that the compressive strength and splitting tensile strength of concrete at each age basically decrease with the increase of temperature,but when the temperature is not higher than 100℃and the age is not more than 14 days,the strength increases slightly.Under the condition that concrete experiences the same temperature,the earlier the age at high temperature,the lower the strength.With the increase of curing time after high temperature,the strength of concrete gradually recovers,and the earlier the high temperature age,the higher the recovery degree,but the increase of strength recovery gradually decreases.