EXPERIMENTS ON CHLORIDE ION PENETRATION INTO HARDENED CEMENT MATRIX

氯离子在硬化水泥中的迁移不仅与其浓度梯度的扩散有关，而且与离子对硬化水泥微观结构的固定有关。本研究将水泥浆体浸泡在盐水中，测量了水泥浆体中总氯离子含量和氯离子在孔溶液中的分布，为建立氯离子在硬化水泥中迁移的数值模型和氯离子在水泥浆体中的浓缩和固定现象提供了必要的数据。有关氯离子在水泥浆体中迁移的试验结果可以概括如下：1)总氯离子含量随着样品表面附近水灰比的降低而增加，2)孔道内氯离子溶液增稠，低水灰比试件在1%~3%盐水中浸泡后，孔道溶液氯离子含量高于表层盐水浓度。另一方面，在盐水浓度为10%时，抑制了氯离子的渗透，使孔隙溶液的氯离子含量低于盐水浓度。3)当水灰比较高时，固定氯离子含量在表面附近往往比内部小。

The transfer of chloride ion in hardened cement matrix is related not only to their diffusion due to the gradient of concentration but also to the fixation of ion to the micro structure of the hardened cement matrix.In this study cement paste specimens were immersed in salt water and the total chloride ion content of cement paste and the distribution of the chloride ions in the pore solution were measured in order to obtain the necessary data for establishing a numerical model representing the transfer of chloride ion in hardened cement matrix and the phenomena of concentration and fixation of chloride ion.The findings of the tests concerning the transfer of chloride ions in cement paste may be summarised as follows.1) The total chloride ion content increases as the water cement ratio decreases near the specimen surface, and increases as the water cement ratio increases in the inner sections.2) Thickening of the chloride solution is observed in pores, with the pore solution chloride ion content being higher than the salt water concentration in the surface layer of specimens with low water cement ratio immersed in 1 to 3% salt water. At a salt water concentration of 10%, on the other hand, the penetration of the chloride ions is checked, making the pore solution chloride content lower than the salt water concentration.3) When the water-cement ratio is high, the fixed chloride ion content tends to be smaller near the surface than inner sections.