水泥砂浆复合受力破坏准则的试验研究

Experimental Study on Failure Criterion of Mortar under Combined Stresses

参考常用的混凝土强度,设计了4种配合比水泥砂浆.采用拉拔测试仪(limpet pull-offtester)测得的水泥砂浆直接拉伸强度大约为其劈裂抗拉强度的60%.采用自行设计的水泥砂浆拉剪、压剪耦合受力装置,测量不同压应力水平下水泥砂浆的抗剪强度.结果表明,当压应力水平大于0.6倍水泥砂浆轴心抗压强度时,其抗剪强度会有不同程度下降.通过数据拟合获得了水泥砂浆复合受力状态下的破坏准则.该准则可以应用于细观力学模型中对混凝土材料破坏过程进行数值模拟;也可作为砌体结构中砂浆的破坏准则.

Four kinds of mortar with different water-cement ratio were designed according to a common range of concrete strength.Tensile strength of mortar was obtained using limpet pull-off tester,and it was about 0.6 times splitting tensile strength of the mortar.Shear strengths of mortar under different normal stresses were obtained using the loading equipments under combined stresses of compression/tension and shear designed.It is found that the shear strength decreases when the normal stress is larger than 0.6 times axial compressive strength of mortar.Failure criterion of mortar under combined stresses was obtained by data fitting.The failure criterion can be used in mesoscopic mechanical models to simulate the fracture of concrete.It can also be used in masonry structures to describe the mechanical behavior of mortar.