粉煤灰基地质聚合物凝结时间的影响因素研究

以粉煤灰为原料,系统研究了水玻璃模数及掺量、水胶比、温度、外掺剂等参数对粉煤灰基地质聚合物凝结时间的影响。研究结果表明,随着温度升高,地质聚合物凝结时间显著降低; 在10 ℃条件下,地质聚合物凝结时间随着水玻璃掺量增加而增加,随水玻璃模数增加先增加后减小,水胶比对地质聚合物凝结时间影响较小,掺入Ca(OH)₂会促进地质聚合物的凝结。在粉煤灰掺量100%、水玻璃模数1.2、水玻璃掺量8%、水胶比0.35、养护温度10 ℃条件下,地质聚合物的初凝及终凝时间分别为65 min和114 min,在养护3 d和28 d后,地质聚合物的强度分别为23 MPa和51.7 MPa。

Influencing Factors for Setting Time of Fly Ash-based Geopolymer

With fly ash as the raw material, the effects of some parameters, including modulus and dosage of water glass, water-gel ratio, temperature and additive agent, on the setting time of fly ash-based geopolymers were systematically studied. The results show that as the temperature rises, the setting time of the geopolymer decreases significantly. At the temperature of 10 ℃, the setting time of the geopolymer increases with the increase of the dosage of water glass, but it increases first and then decreases with the increase in the modulus of water glass. It is found that the water-gel ratio has little effect on the setting time of geopolymers, while the addition of Ca(OH)₂ will promote the setting of geopolymers. With the addition amount of fly ash at 100%, water glass modulus of 1.2, dosage of water glass at 8%, water-gel ratio at 0.35 and curing temperature at 10 ℃, the initial and final setting time of the geopolymer are 65 min and 114 min, respectively. After 3-day and 28-day curing, the strength of the geopolymer is up to 23 MPa and 51.7 MPa, respectively.