Durability Design for Cracked Concrete Structures exposed to Carbonation using Stochastic Approach

Degradation of concrete structures occurs continuously during lifetime due to various environmental attacks. Recently, a lot of concrete structures in big cities are easily exposed to carbonation due to increased in the cities. The carbonation depth specially in cracked area occurred in early-aged concrete is severely increased due to increased intrusion through cracks. Thus, durability design considering these durability degradation has been proposed to evaluate durability performance as that of structural safety design. But in deteriorations like salt attack and carbonation, many variations like cover depth, environmental condition, and construction material are included and durability design based on stochastic approach is recently attempted. In this study, durability design using stochastic approach for sound and cracked concrete structures exposed to carbonation is carried out. probability function and probability of failure are derived considering various variables like material (water content, cement content), crack width, carbonation distribution, and cover depth. For efficient application of multi variables, Monte Carlo Simulation technique is applied and the effect of variables on probability of failure is evaluated. Finally, considering for target safety index proposed by Korean Concrete Specification (Durability Part), lifetime of target structures is predicted.