灰粉比对苯丙乳液基水泥复合材料静态力学性能及破坏形态的影响

对不同灰粉比的苯丙乳液基水泥复合材料进行定伸、拉伸和剪切试验，通过测量弹性恢复率、拉伸剪切力学性能指标、变形性能指标、能耗性能指标和负荷位移，研究了灰粉比对苯丙乳液基水泥复合材料定伸黏结性能、拉伸力学性能、剪切力学性能及破坏形态的影响，结合FESEM试验和压汞测孔(MIP)试验结果，分析了灰粉比对苯丙乳液基水泥复合材料力学性能及破坏形态影响规律的微观机制。结果表明:适当增大灰粉比能够改善苯丙乳液基水泥复合材料的微观形貌，优化孔隙结构，提高密实度，显著增强了复合材料的力学性能；随着灰粉比的增大，苯丙乳液基水泥复合材料的定伸黏结性能逐渐降低，拉伸剪切力学性能不断增强，拉伸剪切变形性能和能耗性能均先提升后降低。灰粉比为30%~35%时，苯丙乳液基水泥复合材料的拉伸剪切力学性能最佳；灰粉比为45%时，苯丙乳液基水泥复合材料的拉伸剪切变形性能和能耗性能均低于灰粉比为20%的苯丙乳液基水泥复合材料。随着灰粉比的增大，苯丙乳液基水泥复合材料能够承受的拉伸和剪切负荷位移均先增大后减小，其破坏形态逐步由“内聚破坏”转为“黏结破坏”。 

Effects of cement-powder ratio on static mechanical properties and failure forms of styrene-acrylic emulsion-based cement composites

Fixed tensile, tensile and shear tests were carried out on styrene-acrylic emulsion-based cement composite specimens with six different cement-powder ratios to measure the elastic recovery rate, tensile and shear mechanical performance indicators, deformation performance indicators, energy consumption performance indicators and load displacement of the specimens, thereby the effects of cement-powder ratio on the fixed tensile bonding performance, tensile mechanical properties, shear mechanical properties and failure forms of the specimens were studied. And the microscopic mechanism of cement-powder ratio influencing on the mechanical properties and failure forms of the composite was analyzed based on the results of FE-SEM test and Mercury Intrusion Porosimeter(MIP) test. The results show that increasing the cement-powder ratio appropriately can improve the microstructure and optimize the pore structure of the composite. In addition, it can also improve the compactness and significantly enhance the mechanical properties of the composite. With the increase of the cement-powder ratio, the fixed tensile and bonding performance of the specimens gradually decreases, the tensile and shear mechanical performance are continuously improved, and the tensile and shear deformation performance and energy consumption performance of the specimens firstly increase and then decrease. When the cement-powder ratio is between 30% and 35%, the tensile and shear mechanical properties of the specimens are the best. When the cement-powder ratio is 45%, the tensile and shear deformation performance and energy consumption performance of the specimens are worse than the specimens with the cement-powder ratio of 20%. As the cement-powder ratio increases, the load displacement that the specimens can withstand gradually increases firstly and decreases, and the failure form of the specimens gradually changes from “cohesive failure” to “bond failure”.