Experimental Investigation on Concrete Incorporating Recycled Glass Waste as Partial Replacement of Coarse Aggregate (3/8): Fresh, Mechanical and Durability Properties

This study focuses on the valorization of recycled glass waste as a partial substitute for coarse aggregates (3/8) in the manufacture of concrete, from a perspective of sustainable development and preservation of natural resources. The control concrete (CC) was produced with 100 % natural aggregates, while five experimental formulations (GC-01, GC-02, GC-03, GC-04 and GC-05) were produced by replacing 4 %, 8 %, 10 %, 12 % and 14 % of the natural gravel (3/8) with recycled glass aggregates of the same particle size. A complete experimental campaign was carried out to evaluate the performance of concretes in the fresh state, in the hardened state, and with regard to durability. The properties studied include sag, density, compressive strength, tensile strength, flexural strength, ultrasonic wave propagation speed, sclerometric index, water absorption by capillary action as well as water permeability and sulfate resistance. Experimental results show that concrete containing 4 % and 10 % recycled glass (GC-01 and GC-03) presents the best overall performance. This formulation simultaneously improves the mechanical properties, the quality of the cement matrix and the durability of the concrete while ensuring good workability. On the other hand, higher substitution rates lead to a gradual decrease in performance, mainly due to the reduction in adhesion between the cement paste and glass aggregates as well as the increase in interfacial transition zones. This research confirms that the recycling of glass waste constitutes a sustainable solution, making it possible to reduce the exploitation of natural aggregates while improving certain concrete performances when the substitution rate remains limited.