Performance of concrete containing waste demolished concrete powder as a partial substitute for cement

Abstract

PurposePresent work deals with the partial substitution of cement by waste demolished concrete powder (WDP) for reducing the carbon footprints of concrete.Design/methodology/approachControl specimens and the specimens with 20% WDP as fractional substitute of cement were prepared. The waste powder was thermally activated at 825 °C prior to its use in the mix. The prepared specimens were evaluated in terms of density, workability, mechanical strength, Ultrasonic pulse velocity (UPV) and rebound hammer (RH).FindingsThe results showed that with the substitution, the workability of the mix increased, while the density decreased. A decrement within a 20% limit was found in compressive strength. The UPV and RH results were closely linked to the other results as mentioned above.Research limitations/implicationsThe study deals with only M15 concrete and the substitution level of only 20% as a baseline.Practical implicationsThe concrete containing 20% WDP is lightweight and more workable. Moreover, its strength at 28 days is 14 MPa, only 1 MPa lesser than the characteristic strength.Social implicationsThe WDP can be recycled and the dumping in landfills can be reduced. This is an important effort towards the decarbonation of concrete.Originality/valuePrevious literature indicates that the WDP has been frequently used as a partial replacement of aggregates. However, some traces of secondary hydration were also reported. This work considers the effect of partial substitution of cement by the WDP.