Silicate-, aluminosilicate and calciumsilicate gels for building materials: chemical and mechanical properties during ageing
Silicate-, aluminosilicate and calciumsilicate gels for building materials: chemical and mechanical properties during ageing
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DOI：
10.1127/0935-1221/2010/0022-2070
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发表时间：
2011-01-01
影响因子：
2.1
通讯作者：
Lohaus, Ludger
中科院分区：
文献类型：
--
作者：
Ruescher, Claus H.;Mielcarek, Elzbieta M.;Lohaus, Ludger
以稻壳树皮灰、粉煤灰、矿渣和偏高岭土为原料合成了硅酸盐、硅酸铝和硅酸钙混凝土、水泥和砂浆。用钠和钾水玻璃溶液进行碱活化。通过抗压强度测量，研究了混凝土和砂浆的硬化与时间的关系。采用红外吸收光谱法跟踪水泥浆体的老化过程。将红外吸收峰与硅酸盐、铝硅酸盐玻璃和水玻璃溶液凝聚物的光谱进行了比较。材料在老化开始时抗压强度的增加可以用两种主要结构单元在不同时间尺度上的发展来解释：一种是相当长的硅酸盐链型单元的快速形成，另一种是硅酸盐的缓慢形成，并存在铝铝硅酸盐包围链的三维网络。对链条的保护，防止破坏，成为长期高强度的关键。含大量CaO的矿渣经碱活化后形成水合硅酸钙型相，机械强度显著提高。
Silicate, aluminosilicate and calciumsilicate concretes, cements, and mortars were synthesized based on rice husk-bark ash, fly ash, slag and metakaolin. Alkali activation was done using sodium and potassium waterglass solutions. The hardening of the concretes and mortars was investigated in dependence on time by compressive strength measurements. The ageing of cement pastes was followed by infrared absorption spectroscopy. The infrared absorption peaks were evaluated in comparison to spectra obtained for silicate and aluminosilicate glasses and condensates from waterglass solutions. The increase in compressive strength of the materials at the beginning of ageing can be explained by the development of two main structural units on different time scales: a fast formation of silicate chain type units of considerable length and a slow formation of a silicate and in presence of Al-aluminosilicate three-dimensional network enclosing the chains. The protection of the chains against destruction becomes crucial for long term high strength. Alkali activation of slag containing significant amounts of CaO leads to the formation of calcium silicate hydrate type phases and strongly enhanced mechanical strength.