活性粉末混凝土冻融循环前后NaCl溶液的吸入特性

Absorption characteristic of reactive powder concrete on NaCl solution before and after freeze-thaw cycles

摘要:

为更好地理解混凝土盐冻破坏机理,研究了NaCl溶液中NaCl质量分数对活性粉末混凝土溶液吸入量的影响规律,并比较了试件表面及芯部吸入面溶液吸入特性的差异;分析了冻融循环1 000次对溶液吸入特性的影响,给出了不同吸入面的毛细吸液系数．研究表明:活性粉末混凝土毛细吸液量随着NaCl质量分数的增大而减小;15～180 min和180～540 min两阶段溶液吸入量均与t1／2呈线性关系;试件表面毛细吸液系数远小于芯部;冻融循环1 000次后溶液吸入量显著降低,仅为冻融循环前的0.33倍;冻融循环1 000次后距离试件表面越远的吸入面毛细吸液系数越大．

Abstract:

To better understand the mechanism of concrete frost damage, the influence of NaCl concentration on the absorbed solution amount of reactive powder concrete was investigated. The difference of absorption characteristic between specimen surface and core were correspondingly compared, the absorption characteristics of specimens after 1000 freeze-thaw cycles were studied, and the capillary absorption coefficients of different areas were calculated. Results show that the absorbed solution amount of reactive powder concrete decreases with the increase of NaCl concentration, and it has a linear relation with the t1／2 during 15～180 min and 180～540 min, respectively. The capillary absorption coefficients of specimen surface are much smaller than that of the core. However, the solution absorption of specimens after 1000 freeze-thaw cycles significantly declines, which is only 0.33 times of that before freeze-thaw cycles. The capillary absorption coefficients of specimens after 1000 freeze-thaw cycles are larger in test area which locate farther from the surface of specimen.