다층구조확산을 고려한 제설제에 노출된 콘크리트의 염화물 해석

Abstract

Concrete is cost-benefit and high-durable construction material, however durability problem can be caused due to steel corrosion under chloride attack. Recently deicing salt has been widely spread in snowing season, which accelerates micro-cracks and scaling in surface concrete and the melted deicing salt causes corrosion in embedded steel. The previous governing equation of Fick's 2nd Law cannot evaluate the deteriorated surface concrete so that another technique is needed for the surface effect. This paper presents chloride penetration analysis technique for concrete subjected to deicing salt utilizing multi-layer diffusion model and time-dependent diffusion behavior. For the work, field investigation results of concrete pavement exposed deicing salt for 18 years are adopted. Through reverse analysis, deteriorated depth and increased diffusion coefficient in the depth are evaluated, which shows 12.5∼15.0mm of deteriorated depth and increased diffusion coefficient by 2.0 times. The proposed technique can be effectively applied to concrete with two different diffusion coefficients considering enhanced or deteriorated surface conditions. ■ keyword :∣Deicing Salt∣Multi-layered Concrete∣Chloride Attack∣Freezing and Thawing∣Time-dependent Diffusion∣