Roller Compacted Concrete with Oil Shale Ash as a Replacement of Cement: Mechanical and Durability Behavior

Oil shale is considered an important source of energy production; however, the burning of oil shale produces deposits that are difficult to be disposed of, which results in serious damage to the environment around us. Since Jordan contains abundant amounts of oil shale, the need to find alternative solutions for exploiting this deposit has become essential. This study aims to investigate the possibility of utilizing oil shale ash (OSA) in the cement industry as a partial replacement for cement in the production of roller-compacted concrete (RCC). Cement was replaced by OSA with replacement levels of 0%, 10%, 20%, 30%, and 40%. Standard cylinders, cubes, and prisms were used to examine the physical properties (density and porosity), mechanical properties (compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity) and durability (Ultrasonic Pulse Velocity (UPV), and compressive strength after cycles of freezing–thawing) of RCC mixes. The results indicated that using OSA at different replacement levels has significantly affected the mechanical properties of RCC mixes as they decreased with the increase of OSA content in the mix but at different rates. The reduction in compressive strength, splitting strength, flexural strength, and modulus of elasticity of RCC was 18–42%, 27–37%, 3–61%, and 3–61%, respectively. However, RCC with OSA reached the required compressive stress for roller compacted concrete that could be used for public traffic or dams according to American Concrete Institute (ACI) requirements. The durability behavior was satisfactory in RCC with different OSA replacement levels compared to control RCC. Based on the experimental results, it is possible to use OSA in producing RCC for up to 30% as a main base coarse.