Experimental Investigation of the Strength and Durability Properties of Concrete using Building Debris and GGBS

The high rate of construction and demolition wastes and the environmental effect involved in the production of Portland cement has augmented the pressure on the need to use sustainable alternatives in the construction technology of concrete. This is experimental research in the study of mechanical behaviour and durability performance of concrete with recycled aggregate concrete (RAC) made of building debris and ground granulated blast furnace slag (GGBS), respectively, as partial substitutes of natural coarse aggregate and cement, respectively. Concrete with 30% GGBS and 40 % RAC replacements were prepared and their performance was compared to normal concrete. The findings show that the mixed GGBS-RCA mixture produced a 28-day compressive strength of 40.0 MPa, which was comparative to that of the control concrete (39.5 MPa). Split tensile and flexural strength were also improved by a margin of around 6-12 percent as compared to RCA-only concrete. The properties related to durability also improved greatly, and the water absorption, water penetration depth, and permeability to chloride ions were reduced by approximately 16, almost 35, and 49 percent, respectively. This is mainly due to the pozzolanic effect of GGBS on the microstructural densification and hardening of interfacial transition zone. The originality of the current research is the integration of RAC and GGBS, as well as the composite evaluation of mechanical and durability performance. The results indicate that GGBS can be used to address the constraints inherent in using recycled aggregate concrete to justify the possibility of using the building-debris-based concrete in sustainable structural and semi-structural construction.