RELIABILITY APPROACH TO SERVICE LIFE PREDICTION OF CONCRETE EXPOSED TO MARINE ENVIRONMENTS

During their lifetimes, structures are subjected to external actions o r agents that in time may alter them from a safe state to failure or a damaged state. One of the processes that may trigger the onset of cor rosion of steel embedded in concrete is the ingress of chloride ions t hat eventually reach the reinforcement, causing the rupture of the pas sive film. In this paper, a method is proposed for interpretation of i mmersion test results and prediction of the service life of concrete s tructures exposed to chloride ions. Once the chloride profiles are det ermined after the immersion test, a realization of the random diffusio n coefficient is obtained at each point for which there is a measureme nt of the chloride content. These samples are used to estimate the pro bability density function of the diffusion coefficient. A reliability analysis is subsequently performed for 10 different lightweight high-s trength concrete mixes. A reinforced concrete element is considered to have failed when corrosion initiates at the reinforcement, i.e., afte r a certain chloride concentration threshold is reached at the reinfor cement. The probability of corrosion initiation in time is calculated for some of the concrete mixes investigated.