高韧性聚合物水泥砂浆的微观结构和性能研究

Study on microstructure and property of high toughness polymer cement mortar

为提高巷道锚喷防护砂浆的韧性和致密性,减小砂浆支护层厚度,降低材料用量,满足低碳经济发展需求,开展了高聚灰比乙酸乙烯-乙烯共聚乳液(VAE乳液)改性水泥砂浆微观结构和力学性能研究。通过扫描电子显微镜分析了改性水泥砂浆的微观形貌,通过力学试验研究了聚灰比对改性水泥砂浆抗压强度、抗折强度、拉伸强度及变形能力的影响规律,分析了改性水泥砂浆微观形貌与力学性能的关系。研究表明,当聚灰比大于42%时,改性水泥砂浆的结构由水化产物组成的体型网状结构转变为水化产物与VAE柔性聚合物膜互穿组成的网络体型结构,抗压试验的荷载-位移曲线分为弹性阶段、平台阶段和致密化阶段,改性水泥砂浆由脆性材料转变为韧性材料。

In order to improve the toughness and compactness of the protective mortar used for anchor-plate retaining in the roadway,reduce the thickness of the mortar support layer and the amount of material,and meet the needs of low-carbon economic development,the research on the microstructure and mechanical properties of vinyl acetate emulsion(VAE)modified cement mortar with high polymer cement ratio was carried out.Through scanning electron microscope(SEM),the micro morphology of the modified mortar was studied.Through the mechanical performance test,the influence of the polymer-cement ratio on the compressive strength,flexural strength,tensile strength and deformation ability of the modified mortar was studied,and analyzed the relationship between the micro morphology and the change of mechanical properties.The results shown that when the polymer-to-cement ratio was greater than 42%,the structure of the modified mortar was transformed from the network structure composed of hydration products to the interpenetrating network structure composed of hydration products and VAE flexible polymer film.The force-displacement curve in compression test was divided into elastic stage,platform stage and densionization stage.The modified mortar was transformed from brittle material to ductile material.