Questions connected to influence of frost degradation on microstructure and physical properties of water saturated cement mortars and their resistance to cyclic water freezing are the objectives of research. The main aim of the investigation is to analyze the ice-induced deterioration of cement mortars with different water/cement ratios (w/c=0.50 and 0.40) in a accelerated durability tests. The changes of pore size distribution and water absorption coefficient are investigated by means of mercury intrusion porosimetry and capillary absorption test. Additionally, the analysis of the impact of drying temperature (40°C, 60°C, 80°C and 105°C) on the microstructure is introduced.The performed tests enabled to estimate that the destruction of the cement matrix and the range of observed changes depend on the initial pore size distribution and their volume in the cement matrix. It is also established that the increase of transport properties is correlated with the change of pore size distribution. The obtained results allow to conclude a decrease of content of small pores (up to 150nm) and increase of larger pores for mortar with w/c=0.50. Application of superplasticizer, which resulting in reduction of water to cement ratio up to 0.40, allows to obtained resistant to 150 frost cycles cement mortar.
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机译:与霜冻降解对水饱和水泥砂浆微观结构和物理性质的影响的问题是研究的目标目标。调查的主要目的是在加速耐久性试验中分析不同水/水泥比(W / C = 0.50和0.40)的水泥砂浆的冰诱导的水泥损坏。通过汞侵入孔隙瘤和毛细管吸收试验研究了孔径分布和吸水系数的变化。另外,介绍了干燥温度(40℃,60℃,80℃和105°C)在微观结构上的影响的分析。进行的表达测试能够估计水泥矩阵的破坏和范围观察到的变化取决于初始孔径分布及其在水泥基质中的体积。还建立了运输特性的增加与孔径分布的变化相关。所得结果允许得出小孔隙含量(高达150nm)的减少,并增加砂浆的孔的孔= 0.50。超塑化剂的施用,导致水还原到水泥比,允许耐150个霜冻砂浆的耐抗性。
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