Assessment of mechanical and durability properties of composite cement-based recycled aggregate concrete

•Composite cement-based recycled aggregate concrete is developed with 100% recycled coarse aggregate.•Aforesaid concrete mixes are studied for a wide spectrum of w/c ratios ranging from 0.3 to 0.7.•Mechanical and durability properties have been evaluated for aforesaid composite cement-based recycled aggregate concrete.•Obtained results suggest that this concrete can be satisfactorily used for structures as the mechanical and durability properties are within the limits. The decade 2014–2024 is known as the sustainable decade, as a result of which there is a need to develop eco-friendly building materials and adopt sustainable construction practices. Utilizing larger proportions of industrial by-products reduces the carbon footprint on the environment caused by the cement manufacturing process. Also, the demand for natural aggregates is surging rapidly, hence recycled aggregates or recycled concrete coarse aggregates are being used as an alternative to natural aggregates. But there is a lack of studies based on the utilization of composite cement (fly ash and slag as blending materials) along with 100% recycled concrete aggregates. In the present study composite cement-based, recycled aggregate concrete is developed for varying water-cement ratios of 0.3 to 0.7 for 100% replacement of natural aggregates with recycled concrete coarse aggregates. These concretes were studied for mechanical properties and durability properties like water permeability, chloride ion permeability, corrosion resistance and resistance to carbonation. It is concluded from the current study that; the developed concrete consisting of 100% RCA and composite cement exhibits compressive strength between 25 MPa and 60 MPa for decreasing w/c from 0.7 to 0.3 respectively. Also, a well-designed mix with dense aggregate grading, ensures that the carbonation exhibited by this concrete is negligible and satisfies all the durability requirements. Hence it can be employed in the real-time construction of buildings.