具有不同界面相厚度的混凝土动态特性

Dynamic Mechanical Behavior of Concrete with Different Sizes of Interface Transition Zone

在细观层次上,可将混凝土看作由水泥砂浆、粗骨料和界面相组成的三相复合材料。为探讨界面相对混凝土动态力学特性的影响,编写了含界面相的圆形骨料随机分布程序,并对具有不同界面相厚度的混凝土动态破坏过程进行模拟,揭示界面相厚度、粗骨料大小、粗骨料体积分数和试件尺寸对混凝土动态特性的影响规律。研究表明:与普通混凝土相同,含界面相的混凝土表现出明显的尺寸效应;随着界面相厚度的增大,混凝土承载能力逐渐减小;保持界面相厚度和粗骨料尺寸不变时,随着粗骨料体积分数的增加,混凝土承载能力呈先增大后减小趋势;保持粗骨料最小粒径和界面相厚度不变时,随着粗骨料最大粒径的增大,混凝土承载能力呈先增大后减小趋势。

From a micromechanical point of view, concrete was considered as a three-phase composite composed of cement mortar, coarse aggregate and interface transition zone （ITZ） between them. In order to study the influence of ITZ on the dynamic mechanical behavior of concrete,we designed a two dimensional circular coarse aggregate random distribution program to simulate the dynamic failure process of concrete with different ITZ sizes,and analyzed the influences of the ITZ size, the specimen size,and the particle size and the volume fraction of coarse aggregate on the load-carrying capacity of concrete. Numerical simulation showed that the concrete with different ITZ sizes has an obvious size effect. The load-carrying capacity of the concrete with different ITZ sizes decreases with the size of ITZ. When the ITZ size and the particle size of the coarse aggregate are kept unchanged, the load- carrying capacity of the concrete increases at first and then decreases with the volume fraction of the coarse aggregate; when the minimum particle diameter of the coarse aggregate and the ITZ size are kept constant, the load-carrying capacity of the concrete increases at first and then decreases with the increase of the maximum particle diameter of the coarse aggregate.