Effect of vacuum dehydration on gel structure and properties of metakaolin-based geopolymers
Source abstract
Abstract
Abstract In aluminosilicate mineral materials, water plays a significant role during the process of geopolymer reaction and is related closely to the development of the strength and structure. In this work, a geopolymer is synthesized via the reaction of metakaolin with alkaline silicate solutions, including water glass and a NaOH solution. This study investigated the effect of water on the gel structure and properties of metakaolin-based geopolymers. Geopolymer samples were found to fast release water under vacuum and allowed the development of low-defect porous materials. After 3 days of curing in suitable conditions, the samples were treated under vacuum, during which the compressive strength did not decrease. Under vacuum at 120 °C, the residual water of the sample produced using water glass was 8.31% and that of the sample produced using NaOH solution was only 1.08%. The results of XRD and FTIR demonstrated that the sample produced using NaOH solution consisted primarily of NaA zeolite. SEM analysis indicated that the pores in sample growed with increasing H 2 O/Na 2 O molar ratio. Additionally, vacuum dehydration can suppress the formation of micro cracks and reduce the shrinkage of the samples.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Concrete and Cement Materials Research · Building materials and conservation · Innovative concrete reinforcement materials
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