Experimental design of concrete mixtures using recycled plastic, fly ash, and silica nanoparticles

•Mixtures experiments are carried out to study the properties of an alternative concrete.•Natural coarse aggregate and Portland Cement are replaced by plastic and fly ash.•Silica nanoparticles are used to improve the mechanical properties of this concrete.•The proposed concrete mixture can reach a compressive strength exceeding 17 MPa.•This alternative concrete is less permeable than conventional concrete mixtures. Recycled plastic and supplementary cementitious materials can be used to substitute natural aggregates and Portland cement in order to reduce the carbon footprint of the concrete industry. This work uses two mixture designs to understand the effect of adding fly ash (FA), nano-silica (nS), and recycled plastic in the cost and mechanical properties of eco-friendly, structural concrete. Results suggest 44% of coarse aggregate can be replaced by plastic when adding 2.5% of nS and 10% of FA (by CM weight). Results on ion penetration tests further indicated that concrete with plastic, FA, and nS is more durable than conventional concrete.