Chloride penetration in reinforced slag-based concrete beams under combined effects of loads and drying–wetting cycles

Abstract

The use of concrete incorporating slag is necessary due to global environmental concerns, but the decrease in concrete durability caused by environments rich in chloride ions requires more advanced concrete mix designs, especially in coastal areas. The aim of this study was thus to assess the influence of slag addition on the transport of chloride ions in reinforced concrete (RC) beams under sustained bending moments, considering two conditions of environmental chlorine exposure: drying–wetting cycles and soaking. The results showed that the chloride diffusion coefficient (CDC) increased in tension zones and decreased in compression zones when the sustained bending load in the concrete beam was increased. However, it was also found that the addition of slag can significantly reduce the chloride diffusion depth and CDC for both environmental conditions, with a more significant effect under drying–wetting cycles. The chloride concentration on the surface of slag concrete in the compression zone was greater than that in the tension zone and greater than that in both the tension and compression zones of the ordinary concrete. A prediction model was established for describing the chloride penetration characteristics of concrete beams subjected to sustained bending moment. The proposed model is a reasonable approach for predicting chloride distribution in RC beams with slag addition subjected to bending moments.