Optimized Design for Durability: Analysis of Service Life Models Using Life 365 Software

Abstract

The life-365 model was developed by the American Concrete Institute (ACI-365) to estimate the service life of structures in two phases: “corrosion initiation” and “corrosion propagation.” This model, using Fick’s diffusion law, predicts the time for chloride ions to reach the critical concentration at the reinforcement level. For evaluation, parameters such as the water-to-cementitious-material ratio, type and amount of cementitious materials, and chloride environmental conditions are considered. According to this model, the impact of temperature on the diffusion coefficient and the positioning of the structure in chloride-laden environments are evaluated based on the type of structure, environmental conditions, and geographic location. Analyses of the outputs of Life-356 software and Life-cycle cost in various samples, including the effects of rubber additives, magnetic water, and silica fume, showed that adding rubber reduces service life and increases construction costs, while the combination of magnetic water and acidic rubber slightly improves service life but increases costs. The addition of silica fume to the mix design has had a significant impact on reducing permeability and increasing the service life of structures, contributing to the delay of corrosion initiation. The suitable performance observed was from a mix design without rubber but containing silica fume and magnetic water, which extended the corrosion initiation time to 9 years and reduced costs compared to other studied samples. This study also aimed to reduce environmental pollutants and demonstrated that optimized mix designs, such as adding silica fume and magnetic water, could improve the efficiency and durability of structures.