Mechanical performance of green concrete produced with untreated coal waste aggregates

Abstract Recently, researchers have tried to find ways to reduce the negative effects of untreated coal wastes (UCW) on the ecosystem of the region. Recycling untreated coal wastes can however be identified as a practical solution in producing concrete aggregates. The present study investigates the mechanical properties of green concrete having untreated coal wastes. A total of eleven mix designs with different contents of untreated coal waste as aggregates were prepared and the cube, cylinder and prism compressive, tensile and flexural strengths as well as the elastic modulus of specimens were determined. The results revealed that untreated coal waste particles can potentially be reused in manufacturing concrete aggregates. It was also confirmed that selecting an appropriate amount of replacement can contribute to the property improvement of concrete, also suggesting an environmental solution to reducing untreated coal wastes. Therefore, replacing 5% of the aggregate with untreated coal wastes instead of sand and gravel, the mechanical properties increased. On average, in sand and gravel replacement compressive and flexural strength increased about 3–7% and 5–8%, respectively.