Abstract Two sets of activating solutions with increasing sodium hydroxide contents were prepared either with or without silicates. Their buffer capacities, i.e. their ability to resist changes in pH, were determined and compared using the Hammett acidity function, a measure of acidity appropriate for concentrated solutions. This is the first time the Hammett acidity function of sodium silicate solutions has been measured. The effects of the buffer capacity and of the initial Hammett acidity function on the reactivity of metakaolin-based pastes were assessed using isothermal conduction micro-calorimetry. The reactivity of metakaolin in sodium hydroxide solutions is shown to be directly related to the initial Hammett acidity function, whereas for sodium silicate mixtures, the buffer capacity is a more pertinent parameter. The mechanism deduced for the role of hydroxide ions during geopolymerization also highlights the role of silicate species as a hydroxide reservoir that nurtures the dissolution process.

中文翻译：

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地质聚合过程中硅酸盐和氢氧根离子之间的相互作用

摘要 制备了含或不含硅酸盐的两组氢氧化钠含量增加的活化溶液。它们的缓冲能力，即它们抵抗 pH 变化的能力，是使用哈米特酸度函数来确定和比较的，哈米特酸度函数是一种适用于浓缩溶液的酸度度量。这是第一次测量硅酸钠溶液的哈米特酸度函数。使用等温传导微量热法评估缓冲容量和初始哈米特酸度函数对偏高岭土基糊料的反应性的影响。偏高岭土在氢氧化钠溶液中的反应性与初始哈米特酸度函数直接相关，而对于硅酸钠混合物，缓冲容量是一个更相关的参数。