Muhammad Riaz Ahmad , Satya Medepalli , Tiao Wang , Jian-Guo Dai , Yuqian Zheng , Tetsuya Ishida
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引用次数: 0
Abstract
The influence of NaOH on pore structure, reaction kinetics, volume, and morphology of reaction products in high-volume-fly-ash mixtures was explored by two mixing methods: (i) direct addition of 0.2 M, 0.5 M and 1.0 M NaOH solution into cement-FA powder, and (ii) pre-dissolving FA into NaOH solution before mixing with cement. The pre-dissolution technique improved early-age mechanical performance by enhancing Si release, aiding the expedited precipitation of extra C-A-S-H gel. Both methods improved the degree of FA reaction and alite/belite hydration. However, 1.0 M NaOH negatively affected the strength and microstructure properties due to undesirable silica-gel formation, C-A-S-H gel carbonation, and increased capillary pore volume. NaOH concentration has affected the packing density of C-A-S-H gel, where high-pH systems exhibit loosely packed sheet-like clusters. Ca/Si of C-A-S-H gel in low and high pH systems evolved with increased curing age, with low pH system exhibiting high Ca/Si at 90 days.
期刊介绍:
Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.