亜硝酸リチウムによるアルカリ骨材膨張の抑制効果

抄録

The effect of LiNO₂ on the suppression of expansion due to alkali-aggregate reactions was investigated by preparing mortars with a reactive andesite sand and measuring the expansion at the prescribed times of the mortars cured up to 7 months. The test results showed that the addition of LiNO₂ giving a Li/Na mole ratio of 0.4 conspicuously suppressed expansion of mortars stored in a fog box and immersed in 1N NaCl solution at 40°C. Furthermore, none of the mortar specimens containing the amount of LiNO₂ which exceeded a Li/Na mole ratio of 0.8 expanded even under the severe condition of 6 months immersion in 1N NaOH solution at 20°C. Expansion tests of mortars using reactive sand particles impregnated with LiNO₂ solution were conducted as well. The use of the impregnated sand particles was found to suppress expansive alkali-aggregate reactions promoted by the intrusion of Na⁺, Cl^-, and OH^- ions. it was also confirmed that the compressive and tensile strengths of mortars changed little by the application of LiNO₂. The results obtained show that LiNO₂ may be able to use as a chemical admixture for preventing alkali-aggregate expansion of concrete.