冻融循环作用下再生骨料混凝土强度衰减特征与微观机理  

Strength Attenuation Characteristics and Microscopic Mechanism of Recycled Aggregate Concrete under Freeze-thaw Cycles

作　　者：宋宝峰[1] 王丽 李和玉[3] SONG Bao-feng;WANG Li;LI He-yu(School of Urban Construction,Liaodong University,Dandong 118003,China;Dandong Kaian Testing Co.,Ltd.,Dandong 118000,China;College of Urban Construction,Heilongjiang Forestry Vocational and Technical College,Mudanjiang 157011,China)

机构地区：[1]辽东学院城市建设学院,辽宁丹东118003 [2]丹东闿安检测有限公司,辽宁丹东118000 [3]黑龙江林业职业技术学院城市建设学院,黑龙江牡丹江157011

出　　处：《辽东学院学报（自然科学版）》2023年第2期123-129,共7页Journal of Eastern Liaoning University:Natural Science Edition

摘　　要：为探究再生骨料混凝土抗冻性及耐久性,通过单轴压缩试验和计算机层析扫描试验,获得0、30、60、90、180、360次冻融循环条件下再生骨料混凝土强度特征和微观结构的损伤规律。结果表明:随着冻融循环次数增加,再生骨料混凝土的抗压强度和弹性模量逐渐下降,下降速率先慢后快;再生骨料混凝土的裂隙在冻融循环过程中逐渐扩张,CT扫描图像中的孔隙率随循环次数增加呈指数型上升趋势,表明微观结构损伤程度不断提高;弹性模量与孔隙率呈负线性关系,说明采用CT图像预测再生骨料混凝土强度损伤程度为合理可行的;通过微观形态分析,发现冻融循环使得骨料间密实度下降,这是导致再生骨料混凝土发生强度性能弱化的根本原因。In order to explore the frost resistance and durability of recycled aggregate concrete,the strength characteristics and microstructure damage law of recycled aggregate concrete under 0,30,60,90,180 and 360 freeze-thaw cycles were obtained by uniaxial compression test and computer tomography scan test.The results show that with the increase of freeze-thaw cycles,the compressive strength and elastic modulus of recycled aggregate concrete decrease gradually,and the decrease rate is slow first and then fast.The cracks in the recycled aggregate concrete gradually expand during the freeze-thaw cycle,and the porosity in the CT scan image increases exponentially with the number of cycles,indicating that the degree of microstructure damage continues to increase.The negative linear relationship between elastic modulus and porosity shows that it is reasonable and feasible to predict the strength damage degree of recycled aggregate concrete by CT image.Through microscopic morphology analysis,it is found that the freeze-thaw cycle reduces the compactness between aggregates,which is the root cause of the weakening of the strength performance of recycled aggregate concrete.

关 键 词：再生骨料混凝土 冻融循环 强度特征 微观结构 氯盐腐蚀 

分 类 号：TU528[建筑科学—建筑技术科学]