Early-Stage Geopolymerization Process of Metakaolin-Based Geopolymer |
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Authors: | Xiuyu Zhu Hao Qian Hongxiao Wu Quan Zhou Huiping Feng Qiang Zeng Ye Tian Shengqian Ruan Yajun Zhang Shikun Chen Dongming Yan |
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Affiliation: | 1.College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China;2.Engineering Design and Research Institute of Rocket Force, Beijing 100011, China;3.Zhejiang Jiaotou Shengxing Mining Co., Ltd., Shaoxing 312432, China |
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Abstract: | 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. |
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Keywords: | early geopolymerization spatial filling physicochemical coupling model expansion dehydration |
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