Experimental research about performance deterioration of engineered barrier in radioactive waste disposal facility

本研究的目的是探讨（1）化学变化，如Ca（OH）2和C-S-H的Ca/Si比的降低;（2）物理变化，如累积孔体积和阈值孔的增加;（3）电处理的可行性，以评价由于浸出引起的扩散系数变化与孔隙比。研究结果为电处理法研究淋滤蚀变提供了重要数据，并表明了电处理法的可行性。特别地，获得了以下用于电处理的项目。1)C-S-H中Ca（OH）2和Ca/Si比降低。2)累积孔容和孔比增加。可以说，电处理对于评价由于浸出引起的胶凝材料的改变是有用的。3)通过电处理得到的孔隙比与扩散系数之间的关系与前人研究中的模型相似。因此，这一结果显示了电处理对淋滤蚀变的适用性。

The purposes of this research were to investigate 1) the chemical alteration, such as decrease of Ca(OH)2 and Ca/Si ratio of C-S-H, 2) the phyisical alteration, such as increase of cumulative pore volume and threshold pore and 3) the feasivility of the electrical treatment for evaluation of diffusion coefficient alteration due to leaching with void ratio. As the results of this study, the important data were obtained for underestanding the leaching alteration by electrical treatment and indicating the feasivility. Espacially, the following items for using electrical treatment were obtained. 1) Decrease of Ca(OH)2 and Ca/Si ratio of C-S-H were confirmed. 2) Cumulative pore volume and pore ratio were increased. It can be said that the electrical treatment is useful for evaluating the alteration of cementitious material due to leaching. 3) The relationship between void ratio and diffusion coefficient which was obtained by electrical treatment was similar to the modeled one in previous studies. Therefore, this result were showing the applicability of the electrical treatment for leaching alteration.