【摘要】 采用低钙粉煤灰为硅铝质原料,研究矿渣取代率、碱激发剂浓度和水胶比对地聚合物砂浆凝结时间和力学性能的影响,结合SEM-EDS和XRD等分析了粉煤灰地聚合物的微观形貌和物相组成,并对其凝结固化机理进行研究。结果表明:随着碱激发剂浓度的增大,砂浆的初凝时间逐渐延长、终凝时间逐渐缩短,抗压、抗折强度呈先提高后降低的趋势;随着矿渣掺量增加,砂浆的凝结时间大幅度缩短,抗压强度显著提高。随着水胶比的增大,砂浆的凝结时间逐渐延长,强度逐渐降低。SEM结果显示:矿渣的取代率越大,试样的微观结构越致密;碱激发剂浓度过高或过低都会使材料的微观结构变得疏松,强度降低。更多还原

【Abstract】 Low-calcium fly ash was used as the silicon-aluminum raw material to study the influence of slag replacement rate,alkali activator concentration and water-binder ratio on the setting time and mechanical properties of geopolymer mortar. In this study,combined with SEM-EDS and XRD and other technical observations,the microscopic morphology and phase composition of fly ash geopolymers were analyzed,and the mechanism of coagulation and solidification was analyzed. The research results show that as the concentration of alkali activator increases,the initial setting time of the mortar is gradually extended,and the final setting time is gradually shortened. The compressive and flexural strength of the mortar first increases and then decreases. As the slag content increases,the setting time of the mortar is greatly shortened,and the compressive strength is significantly improved. As the water-binder ratio increases,the setting time of the mortar gradually increases and the strength gradually decreases. SEM results show that the greater the substitution rate of slag,the denser the microstructure of the sample. If the concentration of the alkali activator is too high or too low,the microstructure of the material will become loose and the strength will decrease.更多还原