Probabilistic Optimum Percentage of Recycled Aggregates Contaminated with Chloride Ion in Concrete Mix

This paper studies the analysis of probabilistic service life in reinforced concrete structures exposed to chloride penetration and concrete made with recycled aggregate. Therefore, by modeling this procedure, the corrosion process can be better evaluated as well as the structural durability. In this study, such durability properties of concrete samples namely electrical resistance as corrosion and diffusion evaluation indicators have been investigated. The prediction models for durability parameters of concrete is obtained by using the neural network, namely Group Method of Data Handling and linear regression first, then these models are evaluated by using a simple and fast usability new method of probability evaluation, and eventually, the probabilistic values of using recycled aggregates with and without chloride ion pre-contamination and probability of failure in specific service life for achieving an environmentally friendly concrete are calculated. Probabilistic evaluation results reveal that for service lifetime of 25 years in a highly corrosive environment with the humidity of 70%, the temperature of 23 °C and aggregates chloride ion pre-contamination percentage of 3%, 5%, 8%, 10% and with adding 10% silica fume, using of recycled aggregates for above different chloride ion pre-contamination is limited to (100%, 46.60%), (100%, 34.57%), (100%, 16.69%) and (32.72%, 1.20%) for recycled coarse and fine aggregates, respectively. Also, it is concluded that in the mean value of recycled aggregate (50%, 50%) and aggregates chloride ion pre-contamination percentage of 5% and target reliability index 3.0 t β = , the time to corrosion initiate is achieved about 22( ) i t = year .