粉煤灰基地聚合物砂浆组成设计与性能研究

以粉煤灰为主要原材料,矿粉为添加剂,水玻璃和氢氧化钠为复合激发剂,标准砂为细集料,制备地聚合物砂浆。运用三维图与等值线作图分析的方法,探究水胶比与胶砂比这两个组成设计参数对粉煤灰基地聚合物砂浆的流动度、抗压强度、抗折强度的影响规律。试验结果表明水胶比与胶砂比均对粉煤灰基地聚合物砂浆流动度与力学强度影响较大。水胶比在0.4~0.42,胶砂比在0.45~0.5时,制备出的地聚合物砂浆工作性能和力学性能较优。基于地聚合物砂浆脆性较大的特点,应用长度为8 mm与12 mm的PVA纤维进行增韧改性。结果表明,掺量为0.5%的PVA纤维对地聚合物砂浆抗压强度影响不大,但是抗折强度显著提高,延性增强,因此压折比下降,弯曲韧性增强。

Mix Design and Performance Study on the Fly Ash Based Geopolymer Mortars

Fly ash as the raw material, blast furnace slag as the additives, sodium silicate and sodium hydroxide as activators, standard sand as fine aggregate, a kind of fly ash-based geopolymer mortars was made. The effect rules of water-binder ratio and binder-sand ratio on fluidity, compressive strength and flexural strength were researched by three dimensional figure and contour mapping analysis method. Experimental results showed that both of water-binder ratio and binder-sand ratio for fly ash based geopolymer mortars had a great influence on the fluidity and mechanical strength. The manufacture of geopolymer mortars had a better working and engineering performance when water-binder ratio was varied from 0.4 to 0.42 and binder-sand ratio was varied from 0.45~0.5. Based on the great brittleness of geopolymer mortars, 8 mm and 12 mm length PVA fiber were used in toughness modification. Results showed that the dosage of 0.5% PVA fiber had a little influence on the compressive strength of geopolymer mortars, but flexural strength and ductility significantly enhanced, resulting in the drop of compressive strength to flexural strength and the enhancement of flexural toughness.