Performance of sustainable cement mortar containing different types of masonry construction and demolition wastes

Abstract

The primary fine aggregate in cementitious construction is often natural sand or river sand. The construction of masonry blocks, in particular, necessitates using sand as a primary raw material, including a significant proportion ranging from 70 to 90%. The demand for river sand is seeing substantial growth. However, the availability of high-quality river sand is constrained due to regulations imposed on sand extraction from river beds. The adverse environmental repercussions have arisen due to the over-mining of river sand in response to the growing demand. The researchers were motivated by the ongoing challenges to seek a viable and environmentally friendly substitute for river sand. In contrast, Construction and Demolition (C&D) waste is a major environmental issue due to its high volume, potential for hazardous materials, and potential for release of pollutants into the environment. The current study examined the viability of using three specific forms of C&D waste derived from masonry structures as substitutes for river sand in cement mortar production. Cement mortar was made and tested, each with varying C&D waste composition levels of 25, 50, and 75% as sand replacement. The examination included the assessment of physical, mechanical, and durability characteristics. The results suggest that the cement mortar with C&D had better dry and wet compressive strength and equivalent flexural and impact strength to the control mortar. The cement mortar containing C&D waste, excluding concrete block waste, absorbs more water than the control mortar. Only cement mortar with fired clay brick waste shows a minor reduction in strength to acid and alkaline chemicals, comparable to the control mortar. Findings show that C&D waste improves cement mortar strength. However, cement mortar durability remains a concern.