Prediction of Chloride Penetration Depth Rate and Diffusion Coefficient Rate of Concrete from Curing Condition Variations due to Climate Change Effect

Abstract

Recently, many countries including Korea are experiencing serious climatic events, such as heat waves, torrential rain, cold waves, heavy snowfall, and typhoons. In addition, due to the extreme climate events, the construction period of concrete structures tends to be extended, whereby increasing related economic losses. Pushing through construction projects without considering climate change results in low-quality concrete, causing poor constructions humans and consequent casualties and property damages. Moreover, exposure of concrete structures to extreme environmental conditions that involve carbonation, freezing and thawing and to chloride attack environments may reduce the durability of concrete. In the environments of carbonation and chloride attack, concrete structure cured in inadequate curing conditions develops cracks, making it easy for CO2 and chloride to and corrode rebars and reducing durability of concrete. Also, in the environments of repeated freezing and thawing, the inadequately cured concrete develops microcracks through which water infiltrates, resulting in decline in performance. According to the study results, durability generally declines most rapidly in the chloride attack environment among various environmental types. Therefore, to address these issues and provide measures for climate change, this study investigated the effect of climate factors on strength and chloride diffusion coefficient rate of concrete structure by selecting sunlight exposure time and wind speed as the most important curing conditions among various climate factors that affect concrete performance. Regarding the analytical method of experimental results, performance based evaluation (PBE) on concrete strength and durability using Satisfaction Curve is proposed. In addition, the PBEs used in this study are applied to future climate scenarios. It is expected that the optimal mix ratio accounting for climatic change in concrete mixing can be derived using the future climate change scenario.