Microstructural development and resulting mechanical properties of seawater mixed concrete

According to the "Water Report" published by United Nations in 2018 (UN World Water Report, 2018), two thirds of the world's population live in areas that experience water shortage for some time in a year. Ongoing studies and predictions represent that water shortage problem will increase in the near future. Based on that information, many researchers worldwide focus on the subjects such as waste water management, use of seawater for several applications and etc., under the scope of sustainability. Construction industry is represented as one of the moderately water dependent sectors in the "2016 Water Report" (UN World Water Report, 2016) of United Nations. Concrete sector is also one of the big water consumer sectors, since concrete is the most used construction material worldwide. In the scope of this study, the main objective was to understand microstructural development and resulting mechanical properties of seawater concrete. Most of the studies found in literature focused on changes in mechanical behavior when seawater was used as the mix water for concrete. However, the number of studies that examine and explain the reason for changes in mechanical behavior is yet very limited. 8 different concrete mixtures were produced in the scope of this study. Type of mix water (seawater and tap water) and type of cement (PC and Sulfate resisting cement) were varied. Macro synthetic structural fibers were also used to see the effectiveness of these fibers when combined with seawater mixed concrete. Detailed microstructural analyses were carried out as well as mechanical strength tests to understand and evaluate the reasons for changes in the material behavior when seawater was used as the mix water for concrete.