Zhu Xiuyu, Qian Hao, Wu Hongxiao, Zhou Quan, Feng Huiping, Zeng Qiang, Tian Ye, Ruan Shengqian, Zhang Yajun, Chen Shikun, Yan Dongming
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
Engineering Design and Research Institute of Rocket Force, Beijing 100011, China.
Materials (Basel). 2022 Sep 3;15(17):6125. doi: 10.3390/ma15176125.
The geopolymerization of aluminosilicate materials in alkaline environments is a complex physicochemical process that greatly influences the microstructure and engineering performances. This work aims to reveal the geopolymerization process of metakaolin-based geopolymer (MKG) in the first 5 d. Physicochemical characteristics of different evolution stages are disposed of in chronological order. The evolutions of electrical resistivity, dehydration process, volume deformation, and ionic concentration are comprehensively analyzed. Results show that chemical dissolution produces large dismantled fragments rather than small free monomers. The formation of a solid matrix follows the "spatial filling rule", which means that gels grow by locking swelling fragments to form a framework, then densely filling residual space. Based on chemical models, early geopolymerization of MKG can be divided into six stages from the physicochemical perspective as dismantling, locking fixation, free filling, limited filling, second dissolution, and local mending. Those findings expand the understanding of the phase evolution of the early geopolymerization process; thus, the microstructure of MKG can be better manipulated, and its engineering performances can be improved.
铝硅酸盐材料在碱性环境中的地质聚合是一个复杂的物理化学过程，对微观结构和工程性能有很大影响。本工作旨在揭示偏高岭土基地质聚合物（MKG）在前5天的地质聚合过程。按时间顺序处理不同演化阶段的物理化学特征。综合分析了电阻率、脱水过程、体积变形和离子浓度的演化。结果表明，化学溶解产生的是大的解体碎片而非小的游离单体。固体基质的形成遵循“空间填充规则”，即凝胶通过锁定膨胀碎片形成框架，然后密集填充剩余空间而生长。基于化学模型，从物理化学角度来看，MKG的早期地质聚合可分为六个阶段，即解体、锁定固定、自由填充、有限填充、二次溶解和局部修补。这些发现扩展了对早期地质聚合过程相演化的理解；因此，可以更好地控制MKG的微观结构，并提高其工程性能。
