碱激发材料氯离子传输性能测试方法及影响因素研究进展

水泥基材料中氯离子的传输是一个非常复杂的过程。在介绍水泥基材料氯离子传输机理及常用试验方法的基础上,综述了碱激发材料氯离子传输性能测试方法及影响因素。碱激发材料氯离子传输性能受激发剂种类的影响,改变矿渣掺量、碱掺量和水玻璃模数能不同程度地改变体系的氯离子传输性能。快速氯离子渗透试验结果受孔溶液化学组成影响,碱激发材料孔溶液碱性高、化学组成更复杂,孔溶液影响更显著,所以该方法不适用于评价碱激发材料氯离子传输性能。自然扩散试验因时间长而不常用。非稳态电迁移试验是目前快速测试水泥基材料中氯离子传输性能最好的方法,但由于碱激发材料与普通水泥基材料的碱度不同,其变色边界氯离子浓度也会不同,将该方法用于评价碱激发材料时,还需进一步研究测试样品的准备和硝酸银变色边界氯离子浓度。

Advances in Testing Methods and Influencing Factors of Chloride Ion Transport Properties of Alkali-activated Materials

The transportation of chloride ions within cement-based materials is a complicated process. In this paper, the mecha-nism for transportation of chloride ions and the testing methods for Portland cement system are introduced firstly. On that basis, the factors influencing the chloride transportation of alkali-activated materials and the testing methods for chloride transportation properties of alkali-activated materials are reviewed. The type of activators, slag content, alkali dosage and modulus of water-glass is closely related to the chloride penetration resistance of alkali-activated materials. The high alkalinity and complex chemical composition of pore solution of alkali-activated materials hinders the application of rapid chloride penetration test, whose measurements are affected by composition and concentration in pore solution of testing samples. The natural diffusion test is a time-consumption method, which is not commonly used in practical. Unsteady electromigration test is widely applied to rapid determination of the chloride penetration resistance of Portland cement system. However, due to the different alkalinity of materials, the chloride concentration at color change boundary of Portland cement system varies from that of alkali-activated materials. Therefore, the preparation of test samples and the chloride concentration at color change boundary with silver nitrate colorimetric method in alkali-activated materials still need further study.