期刊名称：Journal of Materials and Environmental Science
印刷版ISSN：2028-2508
出版年度：2017
卷号：8
期号：5
页码：1783-1796
出版社：University of Mohammed Premier Oujda
摘要：This work is dealing with the valorization of Moroccan fly ash produced by the coal-fired Jorf Lasfar plant in the preparation of fly ash based geopolymer by alcaline activation. Sodium hydroxide and sodium silicate in appropriate ratio were used as an alkaline activator. The characterization of the raw material and the fly ash - based geopolymer synthezised was undertaken using several analytical methods such as XRD, FTIR , FX and 29Si MAS-RMN. Microstructure studies have been conducted using SEM Microscopy .The result of XRD analysis shows that the geopolymer exhibits an amorphous character with minority crystalline phase. The FTIR Spectra analysis reveals that the spectral band corresponding to Si-O and Al-O is displaced towards lower values. This shift is interpreted as a consequence of the Al penetration into the original structure of the Si-O-Si skeleton as observed analogously in zeolites. According to 29Si RMN MAS investigation, the fly ash based geopolymer contains mainly structures of the types Q4 (2Al) and Q4 (3Al). The microstructure of geopolymer specimens reveals the formation of heterogeneous matrix which consists of a dense continuous gel-like with microcracks and micropores. Thermal stability of fly ash based geopolymer was studied using DSC Calorimetry and shows that the geopolymer possess high thermal properties. The chemical stability was sudied by zetametry, the large negative value of zeta potential obtained indicates the high stability of geopolymer suspensions. Water absorption properties were also undertaken and show that the water absorption of geopolymer paste is lower than that of ordinary portland Cement control samples.
关键词：Fly ash; geopolymer; alcaline activation; characterization microstructure; Thermal stability; Chemical stability; Water absorption
