Strength and durability properties of recycled aggregate concrete blended with hydrated lime and brick powder.

Concrete is an important material for the construction of buildings, and highways. However, natural resources are being depleted by using natural coarse or fine aggregates for the production of concrete. The substitution of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) efficiently manages construction waste and preserves natural resources. In the present study, 50 and 100% NCA have been replaced with RCA for the preparation of recycled aggregate concrete (RAC) with blended hydrated-brick powder (RAC-HBr). Additionally, cement was replaced by 10 and 20% of blended HBr in the preparation of RAC mixes. To investigate the strength and durability properties of RCA-HBr mixtures, compressive strength, water permeability, chloride penetration test, and ultrasonic pulse velocity (UPV) tests were conducted. The outcomes indicate that the optimum percentage of blended HBr enhances the compressive strength of RCA mixes. However, blended HBr positively influenced the RCPT, water permeability, and ultrasonic pulse velocity of the RCA concrete mixes. Further, the RCPT outcomes show that the chance of corrosion was reduced by 20%, while the UPV value confirms that the density of the RAC-HBr mixes was enhanced by 28.7% at the age of 56 days. Furthermore, based on the FESEM and EDS analysis, the pozzolanic materials have densified the concrete matrix by reducing the pores and voids of RAC-HBr mixes. Thus, practically, 100% RCA with blended hydrated lime and brick powder can be used to create M35-grade concrete. The current paper investigates the effect of blended HBr on the properties of RAC. 10% HBr was an optimum percentage which has significantly enhanced the strength and durability characteristics of RAC mixes. CSH gel CH crystals densify the concrete matrix. CSH gel and CH crystals were confirmed from the microstructure analysis through FESEM and EDS analysis. [ABSTRACT FROM AUTHOR]