中文摘要：

基于全级配三维细观混凝土随机模型分析方法,系统研究了混凝土中砂浆和骨料等各组分的受力特点,通过现场试验以及数值模拟分析,揭示了骨料降低砂浆强度的作用机理,提出混凝土宏观抗压强度与砂浆抗压强度间的修正关系,并讨论了骨料体积分数及混凝土强度分别对该修正系数的影响规律.研究表明：骨料的加入会降低水泥基材料的强度;混凝土材料的强度小于相同配比条件下的砂浆;用混凝土强度参数代替砂浆参数进行细观层次分析会造成较大误差,应进行修正;修正系数随骨料体积分数增加而线性增长,与混凝土强度关系不大.

英文摘要：

The stress characteristic of mortar and aggregate in concrete were studied systematically based on the fully-graded 3D random meso-scale concrete model. The mechanism that mixing aggregate into mor- tar weaks the concrete strength was revealed. The correction coefficient between concrete macro-compres- sive strength and mortar compressive strength was experimentally and numerically analyzed. The influence of aggregate volume fraction in concrete and concrete strength on the correction coefficient was discussed in detail. It is demonstrated that the strength of mortar cement material will be weaken by mixing normal ag- gregate and the strength of concrete is lower than that of mortar in the same proportioning condition. There is a significant error if the strength of concrete is directly used to replace the strength of mortar in meso-scale model analysis. The strength should be corrected by the correction coefficient. The strength correction coefficient increases with the aggregate volume fraction, and makes no difference on the strength of concrete.