混凝土盐冻破坏机理(Ⅱ):冻融饱水度和结冰压  

One of Mechanisms on the Deicer-Frost Scaling of Concrete(Ⅱ): Degree of Saturation and Ice-Formation Pressure during Freezing-Thawing Cycles

作　　者：杨全兵[1,2] 

机构地区：[1]同济大学材料工程研究所,上海201804 [2]同济大学先进土木工程材料教育部重点实验室,上海201804

出　　处：《建筑材料学报》2012年第6期741-746,共6页Journal of Building Materials

基　　金：西部交通建设科技项目(2001 318 788 77)

摘　　要：研究了冻融循环条件下NaCl浓度(质量分数)对混凝土内部吸入溶液量和饱水度、溶液结冰膨胀率和结冰压的影响,继而对混凝土盐冻破坏机理进行分析.结果表明:随着NaCl浓度的增加,溶液结冰膨胀率和结冰压平衡值显著降低,但溶液结冰产生结冰压的临界饱水度显著提高;在NaCl溶液中进行冻融循环时,混凝土内部饱水度明显高于水中,且饱水度的增长主要取决于冷冻阶段吸入溶液量,与融化阶段关系很小;2%～6%NaCl溶液将产生最大结冰压,因此中低盐浓度引起的混凝土盐冻破坏最严重.Effects of NaCl concentration（by mass） on the solution absorption and degree of saturation in concrete, and the ice-formation expansion ratio and pressure of solutions were investigated under freezingthawing cycles, and then mechanisms on the deicer-frost scaling of concrete were analyzed. Results show that the equilibrium value of ice-formation expansion ratio and pressure of solutions are significantly reduced with the increase of NaCI concentration, but the critical degree of saturation is obviously enhanced. The degree of saturation in concrete during freezing-thawing cycles in NaC1 solutions are obviously higher than that in water, and the increase in degree of saturation in the concrete mainly depends on the solution absorption during the freezing, and is not related to the thawing. The ice-formation pressure in 2 G-6 G NaCI solution is maximum, so the deicer-frost scaling caused by NaCl solution with the low-medium concentration is most serious.

关 键 词：混凝土 盐冻破坏 结冰压 膨胀 饱水度 机理 

分 类 号：TU528.0[建筑科学—建筑技术科学]