Parameters affecting thaumasite formation in limestone cement mortar
Parameters affecting thaumasite formation in limestone cement mortar
复制标题
DOI：
10.1016/s0958-9465(03)00119-7
复制
发表时间：
2003-12
影响因子：
10.5
通讯作者：
G. Kakali;S. Tsivilis;A. Skaropoulou;J. Sharp;R. Swamy
中科院分区：
文献类型：
--
作者：
G. Kakali;S. Tsivilis;A. Skaropoulou;J. Sharp;R. Swamy
由石灰石水泥制成的混凝土可能由于碳硫硅钙石的形成而表现出缺乏耐久性。本文研究了影响水泥砂浆中碳硫硅钙石形成的因素，特别是石灰石含量、养护条件和所用砂的类型。检查了三种类型的水泥：（i）OPC，（ii）含有15%w/w石灰石的波特兰石灰石水泥和（iii）含有30%w/w石灰石的波特兰石灰石水泥。砂浆标本制备使用石灰质和硅质砂。将试样浸入1.8%MgSO4溶液中，并在（i）5 °C和（ii）25 °C下固化。通过XRD和TGA检查和证实了碳硫硅钙石的形成。此外，还进行了几个月的目视检查、强度测试和超声波脉冲速度测量。它的结论是，砂浆含有石灰石，无论是作为砂或作为水泥的主要成分，遭受在低温下的硫酸盐侵蚀的碳硫硅钙石形式。在室温下，暴露一年后未观察到硫酸盐侵蚀。
Concrete made from limestone cement may exhibit a lack of durability due to the formation of thaumasite. This work deals with the factors affecting thaumasite formation in cement mortars and particularly the limestone content, the curing conditions and the type of sand used. Three types of cement were examined: (i) OPC, (ii) Portland limestone cement containing 15% w/w limestone and (iii) Portland limestone cement containing 30% w/w limestone. Mortar specimens were prepared using calcareous and siliceous sand. The specimens were immersed in a 1.8% MgSO4solution and cured at: (i) 5 °C and (ii) 25 °C. The formation of thaumasite was checked and confirmed by XRD and TGA. In addition visual inspection, strength tests and ultrasonic pulse velocity measurements were carried out for several months. It is concluded that mortars containing limestone, either as sand or as a main constituent of the cement, suffer from the thaumasite form of sulfate attack at low temperature. At room temperature, no sulfate attack was observed after a year of exposure.