地聚合物水泥土最佳拌合方法的试验与探讨

Experiment with the Optimal Mixing Methods of Geopolymer Cement Soil and Its Analysis

为了研究地聚合物水泥土最佳拌合方法,对五种不同拌合方法对应的地聚合物水泥土,分别进行了无侧限抗压强度试验、表观形貌分析及电镜扫描试验,试验结果表明不同拌合方法下地聚合物水泥土的抗压强度、微观结构以及表观形貌具有较大差异。综合考虑各因素,选取了最佳拌合方法,首先按最优含水率配置土样,浸润一昼夜后将其与偏高岭土(干土重的3%)混合,喷入碱激发剂(浓度为50%的NaOH溶液与37.1%的钠水玻璃),再加入水泥(干土重的12%)拌匀,最后喷入水灰比为0.5对应的水量。该方法具有较高的抗压强度,较强度最小值提高了82.8%,且具有较大的峰值应变,较峰值应变最小值提高了2倍。此外,在拌合过程中也可发现该方法对应的混合料非常均匀,并无明显成团现象,且该方法对应的试样在破坏时产生许多细小裂纹,塑性破坏特征较明显。

To study the optimal methed of preparing the geopolymer cement soil, five different mixing methods for geopolymer cement soil were designed, and a series of unconfined compressive tests, apparent morphology analysis and scanning electron microscope tests were conducted. The results show that the compressive strength, microstructure and apparent morphology of geopolymer cement soil under different mixing methods were quite different. Taking all the factors into consideration, the optimum mixing method is as follows: the soil was wetted according to the optimum moisture content, mixes with metakaolin(the percentage of 3% by dry weight) after infiltratting for 24 hours;then the mixture was sprayed with alkali activator (50% NaOH solution and 37.1% sodium silicate), and the cement (the percentage of 12% by dry weight) was put into mixture;finally sprayed into the corresponding amount of water with the water-cement ratio being 0.5. The product had the maximum compressive strength while minimum strength was increased by 82.8%. In addition, the product had a greater failure strain, the minimum value of the failure strain increased by 2 times. Moreover, in the mixing process it was also found that the corresponding mixture was very uniform, and there was no obvious agglomeration. Many small cracks were observed when the specimens were damaged, showing the obvious plastic failure characteristics.