再生混凝土单轴压缩破坏过程细观离散元研究  

Mesoscopic discrete element method study on failure process of recycled concrete under uniaxial compression

作　　者：邢心魁[1,2,3] 唐润东 刘晶 覃荷瑛[1,2,3] XING Xinkui;TANG Rundong;LIU Jing;QIN Heying(School of Civil and Architectural Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Collaborative Innovation Center for Exploration and Material Development of Non-ferrous Concealed Deposits,Guilin 541004,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin 541004,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西桂林541004 [2]广西有色金属隐伏矿床勘察及材料开发协同创新中心,广西桂林541004 [3]广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《混凝土》2024年第6期110-115,120,共7页Concrete

基　　金：国家自然科学基金(51768014);广西创新驱动发展专项(桂科AA 20302006);2023年度广西高校中青年科研基础能力提升项目(2023KY0269)。

摘　　要：老砂浆的存在是再生混凝土与普通混凝土的本质区别,也是影响再生混凝土力学性能的主要因素。基于离散元软件,建立了再生混凝土单轴压缩模型,模拟了再生混凝土单轴压缩下的力学响应与裂纹延伸机制,通过与现有的试验数据对比,验证了数值模型的可靠性。研究表明:当老砂浆强度低时,随着厚度的增加,单轴抗压强度、弹模降低,峰值应变增加;当老砂浆强度较高时,老砂浆厚度对再生混凝土抗压性能影响较小;从细观上看,单轴压缩荷载作用下裂纹首先在界面过渡区产生,逐渐向新老砂浆扩展,直至贯通破坏,其破坏主要由拉伸裂纹主导。The essential difference between recycled concrete and ordinary concrete lies in the existence of old mortar,which is the main factor affecting the mechanical properties of recycled concrete.A discrete element numerical model of recycled concrete under uniaxial compression is established based on DEM software,and the mechanical response and crack propagation mechanism of recycled concrete under uniaxial compression are simulated.The reliability of the numerical model is verified by comparing with the existing experimental data.The results show that when the strength of old mortar is low,the uniaxial compressive strength and elastic modulus decrease and the peak strain increases with the increase of thickness.When the strength of old mortar is high,the thickness of old mortar has little influence on the compressive properties of recycled concrete.From the microscopic perspective,the crack first appears in the interfacial transition zone under uniaxial compression load,and gradually expands to the new and old mortar until the penetration failure,which is dominated by tensile crack.In addition,the proportion of shear crack increases with the increase of loading rate.

关 键 词：颗粒流方法 单轴压缩 老砂浆厚度 裂纹扩展 

分 类 号：TU528.01[建筑科学—建筑技术科学]