聚合物改性结构修补材料设计及性能研究

Design and performance research of polymer modified structural repair materials

利用实验室新开发的聚合物乳液,通过正交试验对比不同水胶比、乳液及乳液掺量对修补砂浆工作、力学性能的影响。并通过空白对照、XRD和SEM试验,分析了乳液对修补砂浆的改性效果及增韧的作用机理。研究结果表明,改性丙烯酸树脂乳液较聚丙烯酸酯乳液及环氧树脂乳液对修补砂浆工作及力学性能更有利。正交试验得到的乳液改性修补砂浆初始流动度达335mm, 28min可初凝,4h抗压强度达到43.8MPa、抗折强度达到6.3MPa,后期强度稳定增长,28d抗压强度达到83.5MPa、抗折强度达到23MPa。同时正交试验得到的修补砂浆较不加乳液时抗冲击和耐磨性能分别提高16.5倍和29.3%,且早期收缩更小。XRD和SEM试验分析结果表明,聚合物乳液失水凝聚在砂浆内部形成了区域连续的空间网状结构,这种结构有效分散了砂浆内部的应力集中,增强了砂浆的韧性,提高了砂浆的力学性能。

The effects of different water-binder ratios, emulsions and emulsion contents on the working and mechanical properties of repair mortar were compared by orthogonal experiments with the newly developed polymer emulsion by the laboratory. Through blank controlled experiment, XRD and SEM experiments, the modification effect and toughening mechanism of emulsion on repair mortar were analyzed. The research results show that the modified acrylic resin emulsion is more favorable to the working and mechanical properties of repair mortar than polyacrylate emulsion and epoxy resin emulsion. The initial fluidity of emulsion modified repair mortar obtained by orthogonal experiment is 335 mm, initial setting can be achieved in 28 min, 4 h compressive strength is 43.8 MPa, the flexural strength is 6.3 MPa, the late strength increases steadily, and the compressive strength and the flexural strength after 28 d is 83.5 MPa and 23 MPa respectively. At the same time, the impact resistance and wear resistance of the repaired mortar obtained by orthogonal experiment are respectively 16.5 times and 29.3% higher than that the condition without emulsion, and the early shrinkage is smaller. The results of XRD and SEM experiments show that the polymer emulsion water loss condenses in the mortar to form a regional continuous spatial network structure, which effectively disperses the stress concentration in the mortar, enhances the toughness of mortar, and improves the mechanical properties of mortar.