Feasibility of recycling waste carbon black in cement mortar production: Environmental life cycle assessment and performance evaluation

Abstract

The feasibility of recycling waste carbon black (WCB) that comes as a byproduct from aluminum industry in cementitious composites production is examined in this research. Experimental work combined with environmental life cycle assessment are conducted to evaluate the possibility of partially replacing cement content with 0%, 5%, 10%, 20%, 30% and 40% WCB. The experimental results indicate that small dosage of WCB can be used to replace up to 10% of cement content without negatively affecting the performance of the mortar. The optimum replacement ratio of 5% cause an enhancement in the compressive strength of the mortar by 25%, did not affect its workability and thermal stability, but elongate its setting time. According to the XRD results, the enhancement attributed to the filling effect as the WCB slightly affect the hydration process. The life cycle assessment results show that using WCB in cement mortar production significantly reduces the emissions to the environment and reduces the disposable amount of such waste material in the landfills thus improves the utilization of the landfill areas and reduces the environmental implications.