Optimizing the compressive strength behavior of iron slag and recycled aggregate concretes

The modern world strives for sustainable development in order to meet present demands without compromising future needs. The surge in global population demands more infrastructure and hence, concrete, due to its lowest embodied energy, and will be used for coming years. Also, the environmental impacts like natural resource degradation, land abuse and carbon dioxide emissions are associated with the concrete demands for sustainability and cleaner creation in construction sector. Likewise, industrial waste management is another rising concern demanding more eco-efficient and cleaner process of waste management. Construction and Demolition waste (CDW) produced from the construction industry is generally being landfilled from over the years and cause ecological imbalance. Similar to CDW, Iron slag (IS) an industrial excess produced from iron and steel manufacturing industry also dump in open lands has posed another serious environmental threat due to toxic nature. To make concrete less impactful on the environment, various industrial wastes have been used as substitutes of natural constituents of concrete. CDW can be processed and graded for substitution of natural coarse aggregate (NCA) in form of recycled concrete aggregates (RCA) whereas, IS has the potential to be used as natural fine aggregates (NFA). The current study is an attempt to statistically analyze and optimize the compressive strength performance of concrete prepared with IS and RCA in normally vibrated concrete. The variation in compressive strength of IS-RCA concrete indicates the feasibility in developing greener concrete production correspondingly aid in efficient disposal of aforesaid industrial wastes. The optimum combination for maximum compressive strength was found out to be 25.570% RCA and 30% IS that yielded a compressive strength of 28.324 MPa which was comparable to the predicted value (28.554 MPa).