水泥混凝土抗盐冻性能影响因素研究

Influence Factors of Frost-Salt Resistance of Cement Concrete

通过室内试验研究了气孔结构、表面性质以及荷载耦合作用对混凝土抗盐冻性能的影响规律。结果表明:气泡间距系数相比含气量对混凝土抗盐冻性能的影响更敏感;当新拌混凝土含气量>6%、硬化混凝土气泡间距系数<0.18 mm时,气泡结构参数对混凝土抗盐冻性能的影响钝化;表面泌水、抹面操作不当除了会引起混凝土表面水泥石强度降低以外,还可能会导致混凝土表面气泡结构参数劣化,降低混凝土的抗盐冻性能;重复荷载和盐冻循环的耦合作用会加剧混凝土的盐冻破坏,一般的室内盐冻试验可能会高估混凝土实体工程使用过程中的抗盐冻性能。

The influence factors on frost-salt resistance of cement concrete including air void systems,surface conditions and loads are studied by indoor test.The results show that the spacing factor has more impact on frost-salt resistance of concrete than air content does.The frost-salt resistance of concrete is not so sensitive if the air content is beyond 6% or the spacing factor is less than 0.18mm.Results also indicate that different surface properties have influence on frost-salt resistance of concrete.Improper operation and surface weeping of concrete will lower the frost-salt resistance of cement concrete by lowering the strength of concrete and degrading the air void structural parameters.And the coupling interaction of load and freeze-deicer scaling cycle will greatly accelerate the frost-salt scaling of concrete.And the general laboratory tests may overrate the frost-salt resistance of concrete in practical engineering.