Chloride Ion Diffusion and Durability Characteristics of Rural-Road Concrete Pavement of South Korea Using Air-Cooled Slag Aggregates

Abstract

In the construction industry, the lack of supply and demand for high-quality natural aggregates is a problem. In the case of South Korea, according to data from the Ministry of Environment, it is predicted that the depletion of aggregate resources will occur in 20 years, considering the amount of aggregate used in construction every year and the amount of natural aggregate. Therefore, it is necessary to develop recycled aggregates that can replace natural aggregates for construction. The purpose of this study is to evaluate the applicability of recyclable air-cooled slag (ACS) aggregates as a substitute material for natural aggregates applied to rural-road pavement concrete. That is, the applicability of rural-road pavement concrete is evaluated by evaluating the strength and durability of rural-road pavement concrete to which an ACS aggregate is applied. Durability was assessed in terms of the chloride ion diffusion, repeated wetting-drying, abrasion resistance, impact resistance, and repeated freezing-thawing tests. The test result showed that the diffusion coefficient of the mixture to which the ACS aggregate was applied was slightly larger. In addition, the diffusion coefficient was slightly larger in the case of applying the air-cooled slag coarse aggregate (GG) than in the case of applying the air-cooled slag fine aggregate (GS). The results of abrasion and impact resistance tests of ACS-aggregate-incorporated rural-road concrete indicated that abrasion and impact resistance decreased as the aggregate content increased. The ACS retained some of the properties of the blast furnace slag. Thus, in repetitive wetting-drying tests, which can cause changes in chemical properties, the ACS aggregate increased the concrete’s long-term residual strength. In addition, the results showed that the relative dynamic elastic modulus targeting repeated freezing-thawing resistance satisfied the 80% target. The freeze-thaw resistance improved as the ACS aggregate content increased. In conclusion, the results of this study showed that the durability of rural-road pavement concrete can be improved experimentally by applying both GG and GS at the same time. Therefore, it is shown that ACS aggregates can be applied to rural-road pavement concrete as a substitute for natural aggregates.