Recycled geopolymer aggregates as coarse aggregates for Portland cement concrete and geopolymer concrete: Effects on mechanical properties

•The recyclability of geopolymer concrete in Portland cement concrete is studied.•Elastic modulus decreased 4% and 13% at 20% and 50% recycled content respectively.•Up to 20% recycled aggregate has no significant effect on flexural strength.•Compressive strength decreased only 14% at 20% recycled aggregate content.•Compressive strength decreased significantly at 50% and 100% recycled content.