酸碱干湿环境煤矸石混凝土抗压强度试验研究

Experimental Study on Compressive Strength of Coal Gangue Concrete under Dry and Wet Cycles with Different pH

为了探究干湿循环环境p H值不同时,掺入不同比例煤矸石骨料的混凝土强度弱化规律,制作混凝土棱柱体试件进行单轴抗压强度试验研究。结果表明:破坏面中断裂煤矸石骨料比例随干湿循坏次数增加而增加,掺入比例为δ=20%~50%时,煤矸石骨料及其周围混凝土成为试件承压的薄弱部位;混凝土试件单轴抗压强度随干湿循环次数与煤矸石骨料掺入量的增大而减小,且减小速度在中、碱性环境中逐渐减慢,而在酸性环境中逐渐加快;碱性环境对于干湿循环造成的煤矸石骨料混凝土强度降低现象起到了一定的缓解作用;干湿循环环境p H值不同时,掺入不同比例煤矸石骨料的混凝土随干湿循环次数的增加弹性模量减小。研究为防治煤矸石混凝土在建筑物服役期中受到酸碱干湿环境影响而逐渐弱化现象提供了一定的科学依据。

In order to investigate the weakening rule of concrete with different proportion of coal gangue aggregate, and dry-wet cycling environment p H, concrete prism specimens are made to study the uniaxial compressive strength. The main conclusions are as follows： the proportion of broken coal gangue aggregate increases with the wet-dry cycles increasing in the failure surface. When δ=20%-50%, coal gangue aggregate and its surrounding concrete becomes the weak parts of the specimen. The uniaxial compressive strength of concrete specimens decreases with the drywet cycles and the amount of coal gangue aggregate, whose rate gradually slows down in the normal or alkaline environment while increases in acidic environment. Alkaline environment plays an important role in the strength reducing of coal gangue aggregate concrete caused by dry-wet cycles. Finally, a theory of MOE weakening of concrete with different proportion of coal gangue aggregate and dry and wet cycling environment p H is obtained. Coal gangue concrete is gradually weakened in the environment of wet-dry cycling, acid and alkali environment, and the study provides a scientific basis for the prevention and treatment of this unhealthy phenomenon.