不同水胶比对玻化微珠保温砂浆性能的影响

研究了当水胶比分别为1.2,1.3,1.4和1.5时,玻化微珠保温砂浆的干燥收缩、抗压强度、抗折强度、干密度、导热系数等性能指标.通过压汞试验和SEM扫描电镜分析,从微观角度进一步揭示了玻化微珠保温砂浆的性能指标随水胶比变化的原因.试验结果表明:玻化微珠保温砂浆的干燥收缩随着水胶比的增大呈现明显增大的趋势;当水胶比一定时,玻化微珠保温砂浆的干燥收缩早期增长速率较快,后期增长速率较慢;当水胶比分别为1.3,1.4和1.5时,玻化微珠保温砂浆的抗压强度、抗折强度、干密度、导热系数与水胶比为1.2时相比均有了较为明显的变化,抗压强度分别下降了13.1%,40.0%和73.8%;抗折强度分别下降了18.8%,35.7%和77.7%;干密度分别减小了8.3%,19.4%和33.3%;导热系数也分别下降了4.6%,11.3%和21.4%.玻化微珠保温砂浆的各项性能随着水胶比的变化,产生了明显的变化.通过压汞试验和SEM分析发现,随着水胶比的增大,玻化微珠保温砂浆内部孔隙增多.

Effect of Different Water to Binder Ratio on Performance of Vitrified Microsphere Insulation Mortar

The drying shrinkage, compressive strength, fracture strength, dry density and thermal conductivity of vitrified microsphere insulation mortar were systematically studied when the water to binder ratio are 1.2, 1.3, 1.4 and 1.5. This study reveals the reason that the performance index of vitrified microsphere insulation mortar depends on the different water to binder ratio by mercury test and SEM scanning electron microscope analysis. The results indicate that the drying shrinkage of the vitrified microsphere insulation mortar increases obviously with the increase of water to binder ratio. When the water to binder ratio is fixed, the growth rate of drying shrinkage of vitrified microsphere insulation mortar is rapid in the early stage but becomes slow in the later stage. When the water to binder ratios are 1.3, 1.4, and 1.5, the compressive strength, flexural strength, dry density and thermal conductivity change obviously compared with those of the vitrified microsphere insulation mortar with the water to binder ratio of 1.2. The compressive strength correspondingly decreases by 13.1%, 40.0% and 73.8%, respectively; flexural strength decreases by 18.8%, 35.7%, and 77.7%, respectively; dry density decreases by 8.3%, 19.4%, and 33.3% respectively; and thermal conductivity also decreases by 4.6%, 11.3% and 21.4%, respectively. The structural performance of the vitrified microsphere insulation mortar varies obviously with the change of water to binder ratio. It is also found that the porosity of vitrified microsphere insulation mortar increases with the increase of water to binder ratio by mercury test and SEM analysis.