Improving concrete pavement performance in relation to combined effects of freeze-thaw cycles and de-icing salt

摘要

Mechanical strength and durability properties are two main challenges to the performance of concrete paving. This research focuses on improving the mechanical properties and resistance to surface scaling against de-icing salt by using different cementitious materials such as hydrated lime, metakaolin, and zeolite to rectify the deficiency seen at early ages. In this regard, mechanical strength, durability properties, thermal analysis, Thermogravimetric analysis (TGA) were investigated. Also, microstructural studies using XRD and SEM-EDX experiments were finally performed comparatively under two different water curing condition and exposure to simultaneous of freeze-thaw cycles and de-icing salt condition. According to the results, compressive strengths and resistance to chloride penetration were enhanced by replacing 15% of cement with either metakaolin or zeolite in lime-based concrete at early ages and long term of maturation. After 55 freeze-thaw cycles, lime-based concrete with metakaolin or zeolite shows 3.5 and 7.3 times less weight loss respectively than the concrete without pozzolan. Also, Ca/Si ratio decreased for all mixture; however, mixtures containing Pozzolan performed better performance against de-icing salt. Microstructural investigation shows that metakaolin and zeolite improve the mixture by forming CSH formation due to the existence of a silica compound. This paper recommends the simultaneous use of zeolite with lime in concrete as a solution to deficiencies commonly associated with concrete pavement. (C) 2021 Elsevier Ltd. All rights reserved.