冻融环境下煤矸石混凝土损伤度评估方法研究

本研究对不同取代率的煤矸石粗集料混凝土冻融后的损伤演化行为及损伤评估方法进行了研究,依据超声波评测法确定损伤层厚度,并对冻融后煤矸石混凝土的抗压强度、损伤层厚度、损伤层特征值的变化规律进行分析；提出以便于工程检测的损伤层作为煤矸石混凝土冻融损伤的评价标准,并通过考虑损伤区域材料的残余强度对所测得的损伤层进行修正。研究结果表明:随着冻融次数的增加,煤矸石混凝土的抗压强度与损伤层特征值逐渐减小,损伤层厚度逐渐增大；引入损伤层修正系数后,冻融损伤度评估结果的精确性显著提高,且随着冻融次数的增加,修正系数逐渐增大,反映出损伤区域材料的残余强度不断减小,实际损伤度逐渐增大的演化行为。

Research on the Evaluation Method of Damage Degree of Coal Gangue Concrete Under Freezing-Thawing

In this paper, the damage evolution behavior and the evaluation method of coal gangue aggregate concrete with different replacement rate under freezing-thawing were studied. The damage layer thickness was determined by ultrasonic evaluation method. The change rule of compressive strength and damage layer thickness and damage layer characteristic value of coal gangue concrete after freezing-thawing were analysed. The damage layer of coal gangue concrete that is convenient for engineering detection was proposed as an evaluation standard for the freeze-thaw damage, and the damage layer was modified by the residual strength of coal gangue concrete in the damage area. The results showed that, the compressive strength and damage layer characteristic value of concrete gradually decreased with the increase of freeze-thaw cycles, and the damage layer thickness gradually increased. After considering the correction coefficient, the evaluation accuracy of freeze-thaw damage degree was improved significantly. With the increase of freeze-thaw cycles, the correction coefficient gradually increased, the law reflected the actual phenomenon that the residual strength of coal gangue concrete in damage area gradually decreased and the freeze-thaw damage degree gradually increased.