Effect of Temperature and Relative Humidity on Chloride Threshold of Concrete
Abstract
This paper aims to study the effect of temperature and relative humidity in environment on threshold chloride content of concrete. The temperature of environment at 30°C and 50°C and the relative humidity of environment at 30% and 90% were studied. In this study, fly ash to binder ratios were kept at 0.20 and 0.40. Silica fume to binder ratio of 0.075 was used. Water to binder ratio of 0.50 was used for all mixes. From the experimental results, at constant relative humidity of 90%, concrete exposed to 30°C of temperature had longer depassivation time than concrete exposed to 50°C of temperature, but had lower threshold chloride content. At constant temperature of 50°C, concrete exposed to 30% of relative humidity had longer depassivation time than concrete exposed to 90% of relative humidity, but also had lower threshold chloride content. When steel corrosion index (CRIDT) was considered, concrete exposed to low temperature environment had higher CRIDT than concrete exposed to high temperature environment. Concrete exposed to low relative humidity environment had also higher CRIDT than concrete exposed to high relative humidity. Concrete containing fly ash with the replacement of 40% had the highest CRIDT. Concrete containing silica fume had higher CRIDT than cement-only concrete.
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References
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