XRD patterns of the raw materials.

This study reports the preparation of geopolymers with a mechanical performance similar to that of cement at room temperature by ground fly ash mixed with a small amount of cement. The grinding time of fly ash raw materials was 0,20,40 and 60 min, respectively. The influence of the grinding degree of the fly ash on the properties and the reaction degree of the geopolymer were investigated by XRD, SEM, EDS, and mercury compression tests. The reaction degree of the fly ash geopolymer was quantified by the selective dissolution method. Increasing the grinding degree of fly ash significantly increased the compressive strength of the geopolymer and the density of the microstructure of materials also increased. Furthermore, porosity and the average pore size decreased and the proportion of small holes in the pores gradually increased. The calculation results were in coincidence with the compressive strength test and the micro-performance test of the material, thus indicating that the selective dissolution method can reflect the influence of the grinding degree on the reaction degree of the geopolymer. Furthermore, the reaction degree of the geopolymer increased as the grinding degree of the fly ash increased. However, the growth rate of the reaction degree for the geopolymer slowed down when the fly ash was ground for more than 40 min.

本研究报道了一种室温制备地质聚合物（geopolymer）的方法：将磨细粉煤灰与少量水泥混合，所得产物的力学性能与水泥基材料相当。实验中粉煤灰原料的磨细时长分别设置为0、20、40和60分钟。本研究采用X射线衍射（XRD）、扫描电子显微镜（SEM）、能量色散X射线光谱（EDS）以及压汞试验，对粉煤灰磨细程度对地质聚合物性能与反应程度的影响进行了探究。本研究通过选择性溶解法定量表征粉煤灰基地质聚合物的反应程度。研究表明，提升粉煤灰的磨细程度可显著提高地质聚合物的抗压强度，同时材料微观结构的致密度亦随之提升；此外，材料的孔隙率与平均孔径均有所降低，而小孔在总孔隙中的占比逐渐升高。计算结果与材料抗压强度测试及微观性能测试结果相符，这表明选择性溶解法能够有效反映磨细程度对地质聚合物反应程度的影响。此外，地质聚合物的反应程度随粉煤灰磨细程度提升而升高，但当粉煤灰磨细时长超过40分钟后，其反应程度的增长速率会出现放缓。