关键词: 混凝土, 苏打盐, 盐蚀, 干湿循环

Abstract:

Da’an City, in the west of Jilin Province, is one of the most severe regions that suffer soil salinization in Songnen Plain. Saline-sodic soil is the main type in this area, and the composition of soluble salts in the soil is similar to that in the environmental water. In order to study the concrete durability under such an exposure condition, experimental work on the effect of the multi-salt and dry-wet cycles on concrete performance was carried out. Water and four solutions of different concentration of multi-salt were prepared and used to simulate the concentration and the main types of the dissolved salts in the saline soil in Da’an region. The durability property of the concrete with five different mix proportions was evaluated through the tests of multi-salt and dry-wet cycles. The experimental results indicated that multi-salt had corrosive action on concrete under the condition of dry-wet cycles, and the higher the concentration of the multi-salt solution, the more severely the concrete was degraded. With the increasing times of dry-wet cycles, the mass of concrete and the dynamic elastic modulus of concrete showed a slight increasing at first, and then reduced after a certain number of dry-wet cycles. Air-entrained concrete and fly ash concrete were found have better behavior under such exposure condition, and much better improvement could be observed in the air-entrained concrete.

Key words: concrete, soda salt, salt corrosion, dry-wet cycle