Chloride diffusivity and service life prediction of RC columns with sustained load under chloride environment

•Synthetic effects of crack width and tension strain are experimentally studied.•Service life prediction model of one and two dimensional states are proposed.•Crack has more adverse effect than tension strain when width is more than 0.07mm. The synthetic effects of crack width and environment actions on chloride diffusivity of reinforced concrete (RC) columns were experimentally studied after the alternative action of 300cycles of freeze-thaw and 75 times of seawater immersion. Cracks and tension strain of concrete were induced by eccentric compression load which was sustained till the alternative action finished. The experimental results show that, when the crack width was less than 0.07mm, the effect of cracks on chloride diffusivity was slight and it could be neglected. When the crack width was more than 0.07mm, cracks accelerated the chloride diffusivity and the synthetic effects of crack and environment on chloride diffusivity was bigger than tension strain. Furthermore, chloride diffusion in one-dimensional and two-dimensional state was respectively considered. And the corresponding service life of RC columns were predicted by Monte-Carlo Method. It was concluded that crack width significantly expedited chloride diffusivity and shortened the service life of RC structures in cold coastal regions or deicing condition.