Rheological behaviour, mechanical performance, and anti-fungal activity of OPC-granite waste composite modified with zinc oxide dust

Abstract

Sustainable disposal of granite waste (GW) and hazardous zinc oxide dust (ZOD) via the clean production of some cementitious pastes is the main target of this study. The rheological performance, setting times, physico-mechanical characteristics, morphological features, phase composition and antifungal activity, were investigated. Six composites have been prepared by blending OPC with different percentages of GW (0, 5, 10, 15, 20, 25 wt%) in addition to the other two green composites containing OPC-25%GW-1%ZOD and OPC-25%GW-2%ZOD. The rheological parameters of the blended fresh pastes have been measured by the Bingham model; the data confirmed that increasing the content of GW as well as elevating temperature up to 45 °C caused a significant increase in viscosity and yield stress. The outcomes of setting times demonstrated that ZOD acted as a strong retarder for hydration reaction. From the economic and environmental point of view, the GW can be used up to 25 wt% cement replacement, as reasonable compressive strength was delivered, 67 MPa after 28-days of curing under tap water. Various hydration products were detected via XRD, TGA/DTGA, FTIR and SEM. According to ASTM D4300-1, OPC-25%GW modified by 2 wt% ZOD demonstrated highly efficient anti-fungal for different micro-organism strains such as Aspergillus niger and Aspergillus terreus, and Aspergillus fumigatus.