Workability of Sustainable Cement Sand Mortar Made with Waste Fine Aggregates

Abstract

This study investigates the application of the Circular Economy (CE) principles in cement-sand mortar by partially replacing natural fine aggregates with recycled materials. The aim is to promote sustainable construction practices while reducing ther environmental impacts associated with sand mining and waste disposal. Three types of recycled aggregates were evaluated: Recycled Concrete Aggregate (RCA), Crushed Brick (CB) aggregates (CBA, CBB, CBC, CBD), and crumb Rubber Aggregates (RB10, RB20, RB40). Each replaced 15% of the sand content by mass for the mineral wastes and by volume for the rubber, across three water-to-cement (w/c) ratios: 0.4, 0.5, and 0.6. The workability was assessed using the flow test as illustrated in [17]. The results revealed that the mortars with RCA and brick aggregates exhibited low workability at lower w/c ratios due to the high water absorption and the rough particle textures of the aggregates. In contrast, Rubberized Mortars (RB) showed excellent flowability across all ratios, attributed to rubber’s non-absorptive nature. Increasing the w/c ratio improved the flow in all mixes, though the rubber aggregates consistently outperformed others. The findings highlight the feasibility of using recycled waste materials, particularly rubber, to produce workable, eco-friendly mortars, supporting the shift toward a more sustainable construction industry.