Abstract
The demand on the utilization of the industrial by-product increased in order to preserve the natural resources and create a sustainable environment for the future generation. Therefore, the present study is focused on the utilization of industrial by-product electric arc furnace slag (EAFS) as the replacement of cement and fine aggregates whereas the plastic aggregate (PA) were replaced with the coarse aggregate. The optimization of the mix design was performed by replacing the cementitious slag (SAC) upto 50%, whereas the slag as the replacement of fine aggregates (SAFA) upto 70%. Also, plastic aggregates (PACA) were replaced with coarse aggregates upto 50%. It is concluded that the 30% replacement of cementitious slag and fine slag aggregate found optimum whereas the same found to be 50% in case of coarse aggregate replacement with plastic aggregate. Further, the combined effect of mix with 30% cement, 50% fine aggregate along with 30% of PA was studied. The flexural strength of mix SCFPA found to be 5.5 MPa whereas the same found to be 5.17 MPa in the mix PACA3 and it shows that the cementitious slag and slag fine aggregate contribute marginally on the resistance under flexure. The tensile strength of combined mixes such as SCFA, SCPA, SFPA and SCFPA was found insignificant, whereas the compressive strength of SCPA mix was found as the worst performer. Further, SEM, XRD and EDS analysis were also conducted in order to study the microstructure of the different mixes. The CSH, ettringite and portlandite were majorly observed and the calcium silicate hydrate is an important compound for measuring the strength and rheological properties of concrete. The ettringite (3CaO•Al2 O3 •3CaSO4 •32H2 O) having a needle-like crystals structure plays an important role in the setting time, strength development and shrinkage of concrete, whereas the portlandite identified as a cubical smooth structure works as a bonding agent.