Long-term Deterioration Mechanisms of Hardened Cement Pastes due to High Concentration Alkali Salt Solution in Radioactive Waste Materials and Its Proposal for Mitigation Countermesure

本文研究了高浓度钠盐溶液诱导混凝土中碱-硅反应的机理。为此，通过实验比较了不同钠盐浸泡砂浆杆的膨胀性能。在硝酸钠和硫酸钠溶液中，复杂化合物水合物的形成过程导致氢氧离子浓度的升高是ASR的主要原因。此外，添加大量粉煤灰和高炉渣对控制砂浆棒的膨胀非常有效。

In this research, the mechanisms of alkali-silica reaction(ASR) in concrete induced by high concentration solutions of sodium salts were investigated. For this purpose, the expansion behavior of mortar bars immersed in various sodium salts was experimentally compared. In sodium nitrate and sodium sulfate solutions, the process of formation of complex compound hydrates and thereby the rise in the concentration of hydroxide ion was the main reason of ASR. Furthermore, the addition of large amounts of fly ash and blast-furnace slag was very effective in controlling the expansion of mortar bars.