NaCl对结冰膨胀率和混凝土溶液吸入量的影响  

Effects of NaCl Concentration on Ice-Formation Expansion and the Solution Absorption by Concrete

作　　者：杨全兵[1] 

机构地区：[1]同济大学先进土木工程材料教育部重点实验室,上海200092

出　　处：《建筑材料学报》2007年第3期266-270,共5页Journal of Building Materials

基　　金：西部交通建设科技项目(2001-318-788-77)

摘　　要：提出了一种测定溶液结冰膨胀率的简易方法,并研究分析了在冷冻过程中,不同NaCl浓度溶液的体积变化规律及其对混凝土溶液吸入量的影响.结果表明,随NaCl浓度的增加,溶液结冰膨胀率与其增长速度均迅速降低,且达到体积稳定的时间变长,但在开始结冰前,溶液收缩率越大,收缩持续的时间愈长;混凝土溶液吸入量随NaCl浓度的提高而增加.理论分析表明,在开始结冰膨胀前,混凝土内部空隙中溶液收缩和空气冷却将产生较大的负压,且随NaCl浓度和饱水度的提高而迅速增大,这将使混凝土周围的溶液更易被吸入混凝土中.A simple method to measure the volume expansion of ice formation （Vice） was proposed in this paper, and the volume change of solutions during the cooling and its effect on the solution absorption by concrete were investigated. Results show that Vice and development rate are reduced with the increase in NaCl concentration, and the time to reach the volume equilibrium is prolonged, but the volume shrinkage of the solution before ice formation is enhanced. The solution absorption by concrete is much enhanced with the increase in NaCl concentration. Theoretical analysis shows that the minus pressure in pores of concrete is generated due to the volume shrinkage of the solution and the cooling of the gas in the pores before the expansion of ice formation, and is significantly enhanced with the increase in the degree of saturation and NaCl concentration, which promotes the solution absorption by concrete. These results are useful for understanding the deicer-frost mechanism better.

关 键 词：混凝土 NACL溶液 结冰膨胀率 溶液吸入量 盐冻机理 

分 类 号：TU528[建筑科学—建筑技术科学]