基于细观模拟的轻骨料混凝土破坏行为及尺寸效应研究?

轻骨料混凝土由于其轻质高强及保温隔热性能好等优点,越来越多被应用于实际工程结构。从细观角度出发,将混凝土材料看作由骨料颗粒、砂浆基质及界面过渡区组成的三相复合材料,建立了考虑混凝土材料非均质性影响的二维细观数值分析模型,模拟研究了轻骨料混凝土与普通混凝土压缩和劈拉破坏行为及尺寸效应的异同,并揭示两者破坏机理。结果表明:轻骨料混凝土压缩及劈拉破坏均造成骨料颗粒的断裂,而普通混凝土破坏时骨料很少破坏;轻骨料混凝土由于脆性较强,与普通混凝土相比有更加明显的压缩强度尺寸效应现象;轻骨料混凝土与普通混凝土存在相似的劈拉强度尺寸效应现象。

Study on Failure Behavior and Size Effect of Lightweight Aggregate Concrete based on Meso-simulation

The lightweight aggregate concrete is widely applied to practical engineering structures due to its advantages of lightweight,high strength and good thermal insulation performance.From a microscopic standpoint,the concrete material is considered as a three-phase composite consisting of aggregate,mortar matrix and interfacial transition zones.A two-dimensional meso-numerical analysis model considering the effect of heterogeneity of concrete material was established.The similarities and differences of compression and splitting failure behavior and size effect between lightweight aggregate concrete and ordinary concrete were studied,and the failure mechanisms of both materials were revealed.The result shows that:the compression and splitting failure of lightweight aggregate concrete cause the fracture of aggregate particles,while the aggregate is intact when the ordinary concrete fails;compared with ordinary concrete,lightweight aggregate concrete has more significant size effect of compressive strength due to its strong brittleness;the size effect of splitting tensile strength of lightweight aggregate concrete is similar to that of ordinary concrete.