Valorisation des déchets plastiques (Les sacs) dans la fabrication des mortiers

Abstract

The frequent use of high-density polyethylene (HDPE) bags, offered at checkouts in stores and markets, has led to several environmental problems as these bags are often discarded after being used only once. The management of plastic waste, especially from plastic bags, is a major environmental challenge worldwide. This thesis explores an innovative approach to valorize these wastes as aggregates in the manufacture of mortars for the construction sector. The study focuses on the effect of incorporating shredded or melt-granulated HDPE bag waste on the mechanical and thermal properties and durability of the mortar. Plastic bag waste is first collected, washed and transformed into aggregates by two processes: mechanical grinding (shredding) or thermal melting. These recycled materials are then integrated into mortar formulations at different percentages of natural sand substitution or at different percentages of addition (addition) to the normal mortar formulation to obtain a composite HDPE mortar. The performance of the composite mortar was evaluated in terms of mechanical strength, durability, and suitability for use in thermal comfort. The results show that it is recommended to use crushed sand, and not exceed a 10% substitution for granulated HDPE to achieve acceptable workability and mechanical strength. The lowest thermal conductivity was detected in the mortar with sand substitution of 4.45% shredded HDPE and 30% fusion-granulated HDPE, with the latter improved by the addition of aluminum waste powder (1% of the cement weight). The incorporation of shredded HDPE bag waste into the mortar with 3% addition or 3% substitution content and a water/cement ratio of 0.5, presented the same workability and mechanical strength close to those of the reference mortar, but superior ductility and durability. This innovative approach could be integrated into sustainable construction practices, thus contributing to environmental protection and the promotion of green building materials.