冻融循环下青砖砌体结构性损伤的演化规律  

The Evolution Law of Structural Damage of Blue Brick Masonry under a Freeze-thaw Cycle

作　　者：别治明 BIE Zhi-ming(Department of Architecture/Henan Technical College of Construction,Zhengzhou 450064,China)

机构地区：[1]河南建筑职业技术学院建筑系,河南郑州450064

出　　处：《山东农业大学学报（自然科学版）》2020年第4期668-672,共5页Journal of Shandong Agricultural University：Natural Science Edition

摘　　要：为研究青砖砌体结构性损伤程度随冻融循环的演化规律,本文对经过0、2、4、6和8次冻融循环后的试样开展力学测试、核磁共振和扫描电镜试验,分析了青砖砌体材料的结构的冻融损伤机理。试验结果表明:青砖砌体材料的轴心抗压强度随冻融次数增加呈指数型下降;青砖砌体材料的孔隙体积含量在0~20次循环过程中保持增长,且增长速率逐渐下降;轴心抗压强度与峰面积为负线性关系,拟合直线的确定性系数R2大于0.99;由扫描电子显微镜试验可以观测青砖砌体材料的微观缺陷随冻融循环次数增加而逐渐发展,主要表现为试样内部的小孔隙逐渐形成尺寸较大的裂隙;微观缺陷的发展是导致力学性能衰减的本质机理。In order to measure the variations of microstructure and mechanical properties of blue brick masonry with the influences of freeze-thaw cycles,the compression tests,Nuclear Magnetic Resonance scans and scanning electron microscope tests were conducted on the samples of blue brick with multiple freeze-thaw cycles.The results show that the compression strength of the blue brick decreases exponentially with the increase of cycle number.The spectral area of distribution curves of samples measured by nuclear magnetic resonance measurements keeps increasing during 0~50 freeze-thaw cycles,and the growth rate gradually decreases.There is a good linear relationship between strength and areas with the square R2 of the fitting line correlation coefficient was greater than 0.98.SEM results can prove the microscopic damage of blue brick masonry with the freeze-thaw cycles cause the cement between particles to gradually decompose and disappear,meanwhile pores in the samples become larger.The development of microscopic defects is the essential mechanism that leads to the attenuation of mechanical properties.

关 键 词：青砖砌体 冻融循环 结构性损伤 演化规律 

分 类 号：TU5[建筑科学—建筑技术科学]