Service life model of concrete structures in chloride laden environment

Service life prediction that involves modeling the rate of chloride ingress is complicated by the variety of complex mechanisms involved in both the uptake of chlorides from the external sources and the processes that influence penetration through the cover. The service life model for concrete structures in chloride laden environments consists of the following serial phase: diffusion to the depth of the steel that would precipitate first maintenance actions; corrosion of the steel at the first maintenance depth until cracking and spalling occurs; continue spalling until a damage level is reached which is defined as the end-of-functional service life for an element or structure. The diffusion phase is described by Fick's Law and the boundary conditions define the solution form. The time-to-cracking model is depend upon factors as concrete strength properties, cover depth and corrosion rate. The utility of the model in estimating the service life of corrosion protection systems such as increased cover depth, corrosion inhibitors and low permeable concrete is presented. Also the means for determining the time-to-first maintenance and annual maintenance requirements to the end-of-functional service life are presented. This service life model is applicable to all concrete structures in chloride laden environments as coastal structures and parking garages.