高温后自燃煤矸石骨料混凝土的抗压性能

Compressive Performance of Self-combustion Gangue Aggregate Concrete after High Temperature

为保证自燃煤矸石骨料混凝土在实际工程中的安全运用,制备了172块取代率均为100%的自燃煤矸石粗、细骨料单掺以及同掺的混凝土立方体试件,进行20,100,300,450,600,750℃下的常温和高温试验.通过测定高温前后的混凝土质量、抗压强度和劈拉强度,研究了自燃煤矸石骨料混凝土的高温后性能.结果表明:随着温度升高,试件表面颜色均由青灰色变为灰褐色,最后变为灰白色;试件表面龟裂逐渐增多,其中单掺自燃煤矸石细骨料的试件出现了爆裂现象;质量烧失率随着温度升高及自燃煤矸石骨料用量的增大而增大;自燃煤矸石骨料混凝土高温后的抗压强度和劈拉强度损失皆小于普通混凝土;根据最高受火温度和质量烧失率建立了高温后自燃煤矸石骨料混凝土抗压强度评估公式,与实测结果比较后发现,两者吻合较好.

In order to ensure the safe application of self-combustion gangue aggregate concrete in practical engineering,172 specimens of concrete,were totally replaced by self-combustion gangue fine aggregate,coarse aggregate or both and tested at the temperature of 20,100,300,450,600,750℃.The mechanical properties of self-combustion gangue aggregate concrete were investigated by measuring the mass,compressive strength and splitting tensile strength of specimens before and after high temperature treatment.The results indicate that with the increase of temperature,color of surface change from steel gray to brown gray,finally to grayish white.Cracks on the surface of specimens increase gradually,and the specimens mixed self-combustion gangue fine aggregate appear bursting.The mass loss rate increases with the increasing temperature and the replacement percentages of the self-combustion gangue aggregate.The compressive and splitting tensile strength loss of self-combustion gangue aggregate concrete is less than that of ordinary concrete.Based on the highest temperature and the mass loss rate,the formula which is used to calculate the strength of the self-combustion gangue aggregate concrete after high temperature is established,which is in good agreement with the measured results.