Multifunctional cementitious blends containing zirconia nanoparticles: Mechanical characteristics, gamma attenuation behavior, and self-cleaning performance

Abstract

Marble dust (MD) is an industrial solid waste that has a low recycling rate which triggers in much serious environmental pollution. This study focused on evaluating the possibility of recycling MD as a partial replacing material for Portland cement. To overcome the expected negative impact of MD on the mechanical characteristics of the investigated cement blend because of its inert pozzolanic character, silica fume (SF) was incorporated with it. Hence, this article interested with evaluating the effects of replacing Portland cement with 10 and 20 (mass %) of MD and SF on the mechanical behavior, stability against fire (SAF), bulk density and water absorption of hardened blended pastes. Composite containing 10% of SF and 10%MD showed slight depletion in compressive strength. So, for economic and environment benefits this composition was selected to be the optimum composition for different application and try to elaborate its mechanical characteristics using minor doses of nano ZrO2 (0.25,0.5 and 1%). The formed hydration products and the microstructure of the hardened composites were identified using TGA/DSC, XRD and SEM techniques. γ-rays shielding % of some hardened composites was identified using two intensities (661.6Kev & 1332.5 Kev) γ-rays radiation and results clarified that inclusion of 1%nano ZrO2 significantly elaborate the shielding capability of the hardened composites. Agar diffusion test (ASTM D4300-1) revealed that composite containing 1% nano ZrO2 possessed an excellent antimicrobial activity (self-cleaning) with various microorganisms. The overall outcomes indicated that inclusion of different doses of nano ZrO2 increase the SAF of SM20 composite; being higher for 1% nano ZrO2 and clarified that 80 %OPC +10%SF+10%MD composite admixed with 0.5% ZrO2 exhibited significantly the best mechanical properties. So, this investigation recommended this composition to be the optimum for various special applications.