混凝土界面渗流的集料体积率阈值算法及其影响因素评价

提出了混凝土界面渗流的集料体积率阈值算法并定量评价了影响该阈值的因素.通过引入周期性边界条件,在立方体单元内模拟混凝土中集料和界面的分布.基于模拟的混凝土细观结构,给出了集料体积率阈值算法并讨论了模拟单元边长对界面渗流概率的影响,在该算法的有效性获得实验验证后,定量评价了界面厚度、最大集料直径和集料级配对集料体积率阈值的影响.结果表明:集料体积率阈值随着界面厚度的增大而减小,但随着最大集料直径的增大而增大;集料级配对集料体积率阈值有很大的影响,其影响程度在20%左右,最大集料直径对集料体积率阈值的影响仅为7%.

ALGORITHM FOR THE AGGREGATE VOLUME FRACTION THRESHOLD OF INTERFACIAL TRANSITION ZONE PERCOLATION IN CONCRETE AND EVALUATION OF INFLUENCING FACTORS

An algorithm for the aggregate volume fraction threshold of interfacial transition zone (ITZ) percolation in concrete is presented and the factors that affect the threshold are quantitatively evaluated. By introducing periodic boundary conditions, the distribution of aggregates and ITZs in concrete is simulated within a cubic element. Based on the simulated mesostructure of concrete, an algorithm for the aggregate volume fraction threshold is presented and the effect of the side length of the simulation element on the ITZ percolation probability is discussed. After the validity of the proposed algorithm is verified with the experimental results, the effects of the ITZ thickness, maximum aggregate diameter and aggregate gradation on the aggregate volume fraction threshold are evaluated in a quantitative manner. It is found that the aggregate volume fraction threshold decreases with the increase of the ITZ thickness but increases with the increase of the maximum aggregate diameter. It is also found that the aggregate gradation significantly influences the aggregate volume fraction threshold by about 20%, whereas the extent to which the maximum aggregate diameter influences the aggregate volume fraction threshold is only 7%.