EPS混凝土静态劈裂性能研究

Study on static splitting performance of EPS concrete

试验研究了不同粒径、不同含量聚苯乙烯泡沫混凝土(EPS混凝土)的劈裂性能。线弹性模型的计算结果表明:EPS混凝土劈裂强度表现出一定程度的粒子尺寸效应,粒子尺寸效应随相对密度的降低而减小。通过劈裂试样破坏形态可以看出,由于EPS混凝土在EPS颗粒与水泥浆体界面之间以及断裂过程区存在大量的微裂纹,试样在劈裂破坏中会出现一定数量的次生裂纹,EPS混凝土表现出明显黏性特性。建立EPS混凝土抗拉强度黏聚裂纹模型,计算结果表明:按黏聚裂纹模型计算的EPS混凝土的劈裂强度也表现出明显的粒子尺寸效应,且其计算结果略高于按弹性理论计算的结果,并且两者之间的差异随相对密度的增加而逐渐减小。

An experimental investigation was carried out to study the splitting behavior of polystyrene foam concrete( EPS concrete) with different contents and polystyrene bead sizes. The linear-elastic model calculation results show that the particle size effect of the polystyrene foam affects the splitting strength of EPS concrete,and the particle size effect reduces with the decrease of relative density. Secondary cracks were observed in broken EPS concrete specimens. The secondary cracks were believed to be initiated from a large number of micro-cracks distributed in the mortar matrix around polystyrene foam beads and along the fracture pathways. It is concluded that the viscosity properties of EPS concrete has great impact on the behavior of the concrete. A cohesive crack model was established to study the splitting properties of EPS concrete. The results show that the particle size effect also exists. The solution from the cohesive crack model is slightly higher than that from elastic theoretic model,and the difference decreases with the increase of relative density.