Fine-recycled concrete aggregate based cementitious polymer composite coating for corrosion and biocorrosion protection of concrete reinforcing steel bar

The present study proposes an effective way of utilizing fine-recycled concrete aggregates (f-RCA) in combination with fly ash (FA) and small proportions of rGO/ZnO (reduced graphene oxide/zinc oxide) particles to develop fRCA based composite coating as a biocorrosion resistant coating for rebar protection. As the f-RCA based composite coating lacks stability during long-term direct exposure to bacterial suspension/corrosive medium, the study utilizes a strategy to integrate acrylic based polymer matrix to further enhance the stability and corrosion resistance of the f-RCA based composite coating. In the acrylic based cementitious polymer coating, fRCA- FA- rGO/ZnO composite serves as a partial replacement material to Portland cement, and results in the formation of f-RCA based polymer composite coating with nano-level morphological reformation and smooth topographical features favorable to offer better corrosion resistance (icorr=11.2 +/- 0.17 mu A cm- 2) and low bacterial survivability percentages. This coating exhibits significantly enhanced performance in all the bacterial cultures chosen for the study as compared to the conventional polymer coating and f-RCA based composite coating, during both direct exposure and indirect exposure through embedding in real concrete specimen.