An Experimental Study On The Long-term Properties Of Resistance To Chloride Ions Into Concrete Added With Mineral Admixtures

It is of significance for predicting the srivice life of reinforced concrete structures located in the chloride laden environment to study the influential factors that affects the chloride diffusivity of concrete. With the water/binder ratio, the aggregate volume fraction, and the type and content of mineral admixtures being the variables, the chloride diffusivity of concrete is measured and the effects of these factors on the chloride diffusivity of concrete are evaluated in a quantitative manner.The experimental results show that, as the curing time increases, the chloride diffusivity of concrete added with mineral admixtures decreases but the percentage of decrease reduces gradually. For a given aggregate volume fraction, the chloride diffusivity of concrete added with mineral admixtures increases with the increase of the water/binder ratio and a larger water/binder ratio results in a more significant decrease in the chloride diffusivity of concrete with the curing time. For a given water/binder ratio,the chloride diffusivity of concrete added with mineral admixtures decrease with increasing the aggregate volume fraction and a larger aggregate volume fraction results in a more significant decrease in the chloridediffusivity of concrete with the curing time. Addition of mineral admixture to concrete can significantly reduce the chloride diffusivity of concrete and slag is better than fly ash in improving the property of resistance to chloride ions into concrete.It is found from the experimental data that the water/binder ratio and the content of mineral admixtures are two most important factors influencing the decay coefficient of the chloride diffusivity of concrete. A regression formula of the chloride diffusivity of concrete added with mineral admixtures is given and preliminarily verified with experimental results.