Investigation the effect of coal waste on Mechanical performance of green concrete

The reduction of natural resources makes researchers to revise the natural aggregates and find ways to reduce the negative effects of untreated wastes on the ecosystem of the region, so they have tried to increase the use of industrial waste material. In order to study the effect of untreated waste coal on mechanical performance of green concrete 9 mix designs with different contents of untreated coal waste (5%, 10%, 15%, 20%) as coarse and fine aggregates and constant water to cement ratio (w/c=0.4) were prepared. The results show that, replacing 10% of the aggregate with untreated coal waste instead of sand and gravel, compressive strength, elastic modulus and ultrasonic pulse velocity increase compared to plain concrete (without untreated coal waste). However, by increasing the percentage of coal waste, the tensile strength of the concrete specimens decrease compared to plain concrete. Thus selecting an appropriate amount of replacement untreated coal waste as a substitute for aggregate in concrete not only minimizes the negative impact of waste coal dumps, but also it can improve some properties of concrete, and be considered as a step toward sustainability.