The effects of calcium hydroxide and activator chemistry on alkali-activated metakaolin pastes
The effects of calcium hydroxide and activator chemistry on alkali-activated metakaolin pastes
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DOI：
10.1016/j.cemconres.2021.106453
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发表时间：
2021-04-18
影响因子：
11.4
通讯作者：
White, Claire E.
中科院分区：
文献类型：
--
作者：
Alventosa, Karina M. L.;White, Claire E.
介绍氢氧化钙作为氢氧化钠和硅酸盐活化偏高岭土浆料添加剂的影响，主要目的是确定钙对反应动力学和相形成的具体影响。采用 FTIR 和 XRD 来了解氢氧化钙（10 wt% 替代偏高岭土）在 1、5 和 10 M NaOH 活化糊（以及等摩尔浓度 Na2SiO3 活化糊）中的相互作用，重点关注其对硅铝酸钠水合物 (N-A-S-(H)) 凝胶纳米级特性的影响。原位 FTIR 和 ICC 用于评估氢氧化钙对反应动力学的影响，包括偏高岭土溶解速率和相关的 N-A-S-(H) 凝胶生长速率。研究发现，氢氧化钙可有效加速 5 M Na2SiO3 活化偏高岭土的反应动力学，因为它形成了初始富钙凝胶，促进了额外的偏高岭土溶解并增强了 N-A-S-(H) 凝胶的形成。
The impact of calcium hydroxide as an additive in sodium hydroxide- and silicate-activated metakaolin pastes is presented with a primary aim to ascertain the specific effects of calcium on the reaction kinetics and phase formation. FTIR and XRD are employed to understand the interaction of calcium hydroxide (10 wt% replacement of metakaolin) in 1, 5 and 10 M NaOH-activated pastes (and equivalent molarity Na2SiO3-activated pastes), with a focus on its impact on the nanoscale properties of the sodium-alumino-silicate-hydrate (N-A-S-(H)) gel. In situ FTIR and ICC are used to assess the impact of calcium hydroxide on the reaction kinetics, including the rate of metakaolin dissolution and associated rate of N-A-S-(H) gel growth. It is found that calcium hydroxide is effective at accelerating the reaction kinetics of 5 M Na2SiO3 -activated metakaolin due to the formation of an initial calcium-rich gel that promotes additional metakaolin dissolution and enhances N-A-S-(H) gel formation.