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本文研究了丙烯酸乳液与苯丙乳液对快硬硫铝酸盐水泥砂浆抗折强度、抗压强度、粘结强度等力学性能的影响,并改性水泥试块进行XRD、SEM、孔结构等微观分析。实验结果表明:乳液的掺入延缓了硫铝酸盐水泥的凝结时间;丙烯酸乳液的改性效果优于苯丙乳液,乳液的加入使砂浆的抗折强度提高37%,粘结抗折强度提高47%;乳液改性水泥砂浆的最佳养护制度为标准箱养护1d+水养2d+自然状态下养护25d。微观分析结果表明:在水化早期,乳液的加入使得未水化的硫铝酸钙、Ca(OH)_2增多,证明聚合物乳液具有缓凝作用;SEM图片显示改性水泥砂浆结构更加密实,使得砂浆的力学性能得到提高。聚合物乳液改性水泥砂浆的孔隙率下降,内部孔隙结构得到改善,从宏观上提高了其力学强度。
In this paper, the effects of acrylic emulsion and styrene-acrylic emulsion on the mechanical properties such as flexural strength, compressive strength and bond strength of fast-hardening sulphoaluminate cement mortar were studied. The microstructure of the modified cement specimen was analyzed by XRD, SEM and pore structure analysis. The experimental results show that the incorporation of the emulsion slows the setting time of the sulphoaluminate cement; the modification effect of the acrylic emulsion is better than that of the styrene-acrylic emulsion; the addition of the emulsion increases the flexural strength of the mortar by 37% and the bond flexural strength 47%. The best curing system of emulsion modified cement mortar is standard box curing 1d + watering 2d + natural conservation 25d. The results of microanalysis showed that the addition of emulsion made the amount of unhydrated calcium sulphoaluminate and Ca (OH) 2 increase in the early stage of hydration, which proves that the emulsion has retarding effect. The SEM images show that the structure of the modified mortar is more compact, The mechanical properties of mortar are improved. The porosity of polymer mortar modified cement mortar decreased, the internal pore structure was improved, macroscopically enhanced its mechanical strength.