Chloride migration in cement mortars with ultra-low water to binder ratio
Chloride migration in cement mortars with ultra-low water to binder ratio
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DOI：
10.1016/j.cemconcomp.2021.103974
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发表时间：
2021-02-13
影响因子：
10.5
通讯作者：
Wu, Zemei
中科院分区：
文献类型：
--
作者：
Hu, Xiang;Shi, Caijun;Wu, Zemei
研究了辅助胶凝材料对超低水胶比水泥砂浆抗压强度和氯离子渗透性的影响。研究了快速氯离子迁移试验（RCM）在评价混凝土抗氯离子渗透性能中的应用。试验结果表明，通过减小试件厚度和延长试件在饱水过程中的静置时间，可以在足够的试验时间内测定超低水胶比水泥砂浆的氯离子迁移系数。在一定的取代量范围内，矿渣、粉煤灰和硅灰等超细粉体取代水泥后，水泥砂浆的孔结构明显致密，抗压强度和抗氯离子渗透性能提高，尤其是硅灰水泥砂浆。当硅灰与矿渣或粉煤灰复合时，硅灰与矿渣或粉煤灰复合的水泥砂浆性能上级其它复合材料，其抗压强度与孔隙率之间存在良好的线性关系。与总孔隙率相比，水泥砂浆中直径大于20 nm的孔隙体积对氯离子迁移系数的影响更大。
This paper investigates the influences of supplementary cementitious materials (SCMs) on the compressive strength and chloride ion permeability of cement mortar with ultra-low water to binder ratio. The applicable of rapid chloride migration (RCM) test on the evaluation of chloride penetration resistance is studied. Test results show that with the decreased specimen thickness and extended standing time during water saturation process, the chloride migration coefficient of cement mortars with ultra-low water to binder ratio can be measured with sufficient testing duration. Within a specific range of replacement level, the replacement of cement with SCMs such as slag, fly ash and silica fume significantly densifies the pore structure and increase the compressive strength and chloride penetration resistance of cement mortar, especially for the cement mortar with silica fume. When more than one type of SCMs are incorporated, the cement mortars with silica fume and slag or fly ash show superior performance than other mixtures.A good linear relationship exists between compressive strength and porosity of cement mortars. Compared to the total porosity, the chloride migration coefficient is more affected by the volume of pores with diameter larger than 20 nm within cement mortars.