Improving sustainability and compressive strength of fiber reinforced concrete by adding granite powder waste as paste replacement

Fiber reinforced concrete (FRC) typically has large cementitious paste volume and high cementitious content that lead to relatively large carbon footprint and inferior sustainability. Nevertheless, it is envisaged that this problem of FRC may be resolved by adding granite powder waste (GPW) to replace an equal volume of cementitious paste so as to reduce the cement consumption and carbon footprint, recycle the GPW, and thus improve the sustainability. Herein, a series of FRC mixes incorporating polyvinyl alcohol (PVA) fibers and added with GPW to replace part of cementitious paste were produced and tested. The results showed that such paste replacement could reduce the cement consumption by as much as 20%, increase the compressive strength by up to 11%, but decrease the flexural strength by up to 7%. Put together, this could reduce the carbon footprint by as much as 18%, and increase the compressive strength/carbon footprint ratio and flexural strength/carbon footprint ratio by approximately 26% and 19%, respectively. Correlation analysis revealed that the fresh and hardened performances of FRC are highly dependent on its packing density and water film thickness.