The mechanical strength and durability properties of ternary blended cementitious composites containing granite quarry dust (GQD) as natural sand replacement

Abstract

Cementitious composites are the most used man-made materials in the world with a global annual production quantum of 25 billion tonnes worldwide, contributing approximately 5% to the global greenhouse gas emissions. In the initiative to reduce the carbon footprint of cementitious composite production, are growing interests in the large volume reuse of industrial by products such as ground granulated blast-furnace slag (GGBS), pulverized fuel ash (PFA) and granite quarry dust (GQD) in cementitious composites production. Such an approach offers a two-fold solution towards addressing the waste management problem related to those industry by-products. At the same time however; reduction of carbon footprints of cementitious composite materials exists. However, in order to enable scalable applications of such a recycling approach, a comprehensive body of knowledge on the mechanical strength and durability performance of the cementitious composite products containing a large volume of the materials needs to be established. Hence, it is the primary aim of the study to report a comprehensive assessment on the mechanical strength and durability properties of high strength cementitious composites. These materials are produced with a large volume of the aforementioned materials as the primary binder and aggregate phase. Throughout the investigation, high strength cementitious composites mixes were produced with a large volume of PFA and GGBS binder. Then phase coupled with ordinary Portland cement (OPC). GQD was used as the fine aggregate phase in substitution of natural river sand at various level of substitution ranging between 0 and 100% by volume. The cementitious composites were characterized in terms of its fresh cementitious composites. Its flowability and hardened cementitious composites properties mainly bulk density, compressive strength, flexural strength, and Ultrasonic Pulse Velocity were also assessed. In addition, the durability properties such as water absorptivity and porosity were also covered in this experimental program. Pore continuity was assessed in terms of air permeability and capillary absorption of the hardened specimens according to the testing age. This paper has also covered the dimensional stability assessment in terms of drying shrinkage. Besides, a comprehensive microstructural assessment was also performed to examine the microstructure morphology. From the results, we found full incorporation of GQD as NRS without significant impairment to the mechanical, durability and length change performance. Thus, the production of sustainable high strength cementitious composites with large volume recycling of GQD is feasible which in turn reduces the depletion on the natural river sand resources.