基于像素网格法的再生混凝土弹性性能细观分析

摘要

Based on the two-dimensional meso-scale model of recycled concrete with random distribution of recycled aggregates and inside natural aggregates,the finite element method combined with Monte Carlo method was used to simulate the elasticity of recycled concrete in MATLAB.The pixel grid method was used to avoid the difficulty of meshing when the distance between the aggregates is small,and experimental results proved that it can improve the computing efficiency under enough precision.The effects of the random distribution of recycled aggregates and inside natural aggregates,the content of aggregate,the aggregate gradation and the aggregate type on the elastic properties of recycled concrete were studied.The results showed that the random distribution of aggregates is an important factor in elastic properties of recycled concrete.The mean value of elastic parameters of recycled concrete increases with the increase of the elastic properties of aggregate and the content of aggregate.The variability of the elastic parameters increases with the increase of the aggregate content,the difference of the elastic parameters between the recycled aggregate and the new mortar,and the increase of the aggregate size.%基于考虑了再生骨料及其内部天然骨料随机分布的再生混凝土二维细观模型,采用与蒙特卡罗法相结合的有限元方法,通过MATLAB编程仿真实现了再生混凝土弹性问题的数值模拟.利用像素网格法避免了骨料间距离较近时网格划分的困难,试验结果验证表明,此方法在保证计算精度的情况下提高了计算效率.进一步研究了再生骨料及其内部天然骨料随机分布、骨料含量、骨料级配及骨料种类对于再生混凝土弹性性能的影响.结果表明,骨料随机分布是造成再生混凝土弹性性能随机性的重要因素;再生混凝土弹性参数均值随着骨料含量、骨料等效弹性参数的增大而增大,骨料级配对于弹性参数的影响不明显;弹性参数的变异性随着骨料含量、再生骨料与新砂浆弹性参数间差异、骨料粒径的增大而增大,但在实际工程中可忽略骨料含量的影响.