掺合料、早强剂对冻融混凝土Cl^-扩散系数的影响

目的研究粉煤灰、矿粉、掺硫酸钠粉煤灰、掺硫酸钠矿粉混凝土冻融循环后Cl^-扩散系数，解决混凝土冻融循环后的内部结构损伤问题．方法采用慢冻法冻融、NEL法测试冻融循环后混凝土Cl^-扩散系数．结果掺入粉煤灰的质量分数低于30％时，掺入矿粉的质量分数低于40％时，经100次冻融循环后混凝土Cl^-扩散系数均低于基准混凝土．经冻融循环后，掺硫酸钠矿物掺合料的混凝土在一定的矿物掺合料掺量范围内，混凝土Cl^-扩散系数低于基准混凝土．经冻融循环后，掺硫酸钠矿物掺合料的混凝土Cl^-扩散系数高于未掺硫酸钠的矿物掺合料混凝土．结论掺粉煤灰混凝土、掺矿粉混凝土的抗冻性好坏取决于矿物掺合料掺量范围．掺硫酸钠粉煤灰混凝土、掺硫酸钠矿粉混凝土，在一定矿物掺合料的掺量范围内，混凝土抗冻性好于基准混凝土．但是硫酸钠的加入使得混凝土抗冻性比未掺硫酸钠混凝土抗冻性差．

The Study on Chloride-Ion-Diffusion-Coefficient of Concrete Mixed Admixture, Early Strength Agent After Freeze-Thaw Cycling

The NEL method is applied to test the chloride - ion - diffusion - coefficient of concrete. Chlorine ion diffusion coefficient of fly - ash, slag, Na2 SO4 and after freeze - thaw cycling is studied. Then internal structure damage situation of concrete after freeze - thaw cycling is studied too. It is found that the concrete in which the quantity of fly - ash admixtures is lower than 30%, the quantity of slag admixtures is lower than 40% ,chloride ion diffusion coefficient is lower than the datum concrete after 100 freeze - thaw cycling. After the freeze - thaw cycling, in a certain scope of the mineral admixtures quantity the chloride ion diffusion coefficient which is added Na2 SO4 and mineral mixes is lower than datum concrete. After the freeze - thaw cycling, the chloride ion diffusion coefficient of the concrete which is added Na2 SO4 and mineral mixes is higher than the concrete which is added mineral mixes. In a certain scope of the mineral admixtures quantity, the frost - resistance of fly - ash concrete and slag concrete are good and the frost - resistance of Na2SO4 fly- ash concrete and Na2 SO4 slag concrete are better than datum concrete. But the NaESO4 causes the frost -resistance of concrete worse than the concrete which isnt added mineral admixtures.