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通过三点弯曲法测试了聚乙烯醇(PVA)改性水泥砂浆的断裂性能,采用双K断裂模型分析了PVA掺量对改性水泥砂浆断裂参数的影响.结果表明:PVA改性水泥砂浆的裂缝口张开位移和裂缝尖端张开位移均随PVA掺量的增加而增大;当PVA掺量为1.0%(质量分数)时,改性水泥砂浆具有最佳失稳断裂韧度和起裂断裂韧度,较普通水泥砂浆分别提高38.31%和40.82%;PVA改性水泥砂浆的各项断裂参数均与PVA掺量呈二次抛物曲线变化规律.
The fracture behavior of polyvinyl alcohol (PVA) -modified cement mortar was tested by three-point bending method. The effect of PVA content on the fracture parameters of modified cement mortar was analyzed by double K fracture model. The results showed that the PVA modified cement mortar The open displacement of crack mouth and crack tip open displacement both increase with the increase of PVA content. When the content of PVA is 1.0% (mass fraction), the modified cement mortar has the best instability fracture toughness and initiation The fracture toughness is 38.31% and 40.82% higher than that of common cement mortar respectively. All the fracture parameters of PVA modified cement mortar exhibit a quadratic parabolic curve with PVA content.