Interactive powder mixture concept for the preparation of geopolymers with fine porosity

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• 作者：Magdalena Lassinantti Gualtieri ; ^{magdalena.gualtieri@unimore.it" class="auth_mail" title="E-mail the corresponding author} ; Alice Cavallini ; Marcello Romagnoli
• 关键词：Geopolymer ; Flyash ; Foaming ; Interactive powder mixture ; Porosity
• 刊名：Journal of the European Ceramic Society
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：36
• 期：10
• 页码：2641-2646
• 全文大小：1357 K

文摘

A new concept of chemical foaming is proposed for the preparation of geopolymers with fine porosity. The use of an interactive powder mixture of gas releasing agent and carrier particles, potentially combines the benefits of small point sources of gas with easy homogenization in the fresh geopolymer. This concept was exploited here for the preparation of porous flyash-based geopolymers. The interactive powder mixture was a SiC powder containing reactive submicron FeSi/FeSi₂ particles. Premature foaming was avoided due to prolonged induction period and slow reaction rate of the active phase. Samples were characterized using scanning electron microscopy, mercury porosimetry, tree-point bending tests and thermal conductivity measurements. In addition, total porosity was determined using measured apparent and real densities. It was found that fine pore structure (diameter 140 ± 80 μm) not normally obtained using chemical foaming, was achieved in a reproducible manner with this approach.