基于微结构组成的全龄期混凝土强度数值模拟  

Numerical study on the full age strength of concrete based on its microstructure

作　　者：左晓宝[1] 李向南 张于晔[1] 黎亮 Zuo Xiaobao;Li Xiangnan;Zhang Yuye;Li Liang(School of Safety Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学安全科学与工程学院,南京210094

出　　处：《东南大学学报（自然科学版）》2024年第6期1411-1417,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(52078252,52378242)。

摘　　要：为了建立混凝土微结构组成与宏观强度之间的定量关系,并计算混凝土的宏观强度,根据各组成材料的尺度特征,重构了混凝土多尺度几何模型,推导了基于等效夹杂理论的多尺度应力响应方程.利用德鲁克-普拉格屈服准则,建立了混凝土单轴强度的多尺度力学模型,并与文献试验结果对比分析验证了模型的合理性.通过数值模拟,分析了全龄期混凝土强度的演变规律及微结构参数对混凝土强度的影响.结果表明,水化产物的几何形状越偏离于球形,混凝土的强度越高,长和扁椭球形水化产物分别垂直和平行于荷载作用方向时,混凝土的强度达到最高.所建立模型可基于混凝土的微结构组成,在综合考虑各组成材料几何形状、颗粒级配、空间分布、随机取向和相互作用等因素的基础上,计算全龄期混凝土的单轴强度.In order to establish a quantitative relationship between microstructure and macroscopic strength of concrete and further calculate its macroscopic strength,a multiscale geometric model of concrete was reconstructed according to the scale characteristics of constituent materials,and a multiscale stress response equation of concrete was presented based on equivalent inclusion theory.A multiscale mechanical model of uniaxial strength of concrete was established using the Drucker-Prager yield criterion,which was verified via its calculated data and experimental results in the literature.By performing a numerical simulation,the evolution of concrete strength during the curing and the influence of microstructural parameters on the concrete strength were analyzed.Results show that the more the geometry of hydration products deviates from spheroid,the higher the strength of concrete is,and there can occur the highest strength of concrete if hydration products with the shapes of prolate and oblate spheroid are perpendicular and parallel to loading direction,respectively.The established model can calculate the uniaxial strength of concrete during the curing based on its microstructure considering the geometric shape,particle gradation,spatial distribution,random orientation and interaction of constituent materials.

关 键 词：混凝土 多尺度 微结构 宏观强度 数值计算 

分 类 号：TU528.1[建筑科学—建筑技术科学]