Evaluating the mechanical and durability properties of sustainable lightweight concrete incorporating the various proportions of waste pumice aggregate

• Environmental Sustainability: The study addresses environmental challenges associated with the disposal of pumice used in the textile industry, and detailed characterization of apparel industry waste materials, proposing a sustainable solution by repurposing waste pumice aggregate (WPA) in concrete production. • Mechanical Properties Evaluation: The research comprehensively evaluates the mechanical properties of pumice-based concrete at various substitution levels of WPA (20 % to 100 % by volume), comparing them directly with conventional grade C-20 concrete. This includes assessments of workability, density, strength (compressive, tensile, flexural), impact resistance, ultrasonic pulse velocity, and water absorption. • Impact on Properties: Incorporating WPA results in notable reductions in various properties compared to conventional concrete, such as decreased workability (11.69 to 53.25 %), lower densities (12.71–35.48 % reduction), and reduced strengths (9.31–48.91 %, and 12.25–75 % decrease) in compressive and flexural strengths). • Cost-Effectiveness: Despite the reductions in some mechanical properties, the use of WPA proves economically advantageous, offering concrete that is 5.6 % to 28 % more cost-effective than conventional concrete. This highlights the potential for significant cost savings in construction projects while promoting sustainable practices. Traditional waste management faces significant environmental, social, and economic challenges, while concrete's high resource consumption highlights the need for improved, low-density alternatives. Consequently, lightweight concrete (LWC) has emerged as a favored solution. Recent interest in using pumice aggregate in concrete arises from its advantageous properties, such as low unit weight, which enables the construction of lighter buildings and reduces the load on structural elements. This study aimed to create lightweight, sustainable concrete using underutilized waste pumice aggregate (WPA). Concrete specimens with waste pumice aggregate ratios of 20 %, 40 %, 60 %, 80 %, and 100 % were analyzed at 7 and 28 days, with results contrasted against the virgin sample. The testing protocol encompassed detailed laboratory evaluations of concrete properties, including workability, density, strength, impact energy, ultrasonic velocity, water absorption, and cost analysis. Experimental results indicated that the inclusion of Waste pumice aggregate as a lightweight aggregate in concrete, in contrast to conventional aggregates, results in reduced workability, density, and strength metrics, as well as heightened water absorption, diminished impact energy, and lower ultrasonic pulse velocity. Sustainable or green concrete from M-20 to M-60 along strength ≥17 MPa is for load-bearing applications, while M-80 and M-100 whose strength is <17 MPa are for non-load-bearing uses.