Effective use of sawdust for the production of eco-friendly and thermal-energy efficient normal weight and lightweight concretes with tailored fracture properties

In this research, we produced eco-friendly and thermal efficient normal and lightweight concretes with different dosages of sawdust as replacement of sand. Conventional NWC containing 0, 5, 10, and 15% sawdust and LWC containing 0 and 10% sawdust of total dry volume of sand were evaluated in terms of volumetric shrinkage, compressive strength, flexural strength, fracture toughness, water absorption, density, thermal conductivity and energy efficiency. Test results showed that volumetric shrinkage and concrete density decreased while water absorption increased with the increase in sawdust percentage. For NWC and LWC sawdust formulations, the total fracture toughness increased by 10.71% and 14.89% respectively while the rupture strain increased by 58.86% and 37.30% respectively. At 28 days, the compressive strength of NWC and LWC sawdust formulations was more than 34 MPa and 21 MPa respectively and hence these concretes can be used for structural applications. The energy analysis of single room model prepared with sawdust formulations showed significant reduction (up to 21.42%) in heating ventilation and air-conditioning (HVAC) as well as in CO₂ emissions (up to 13%). Conclusively, the utilization of sawdust provides viable source of raw materials for construction industry, eco-friendly solution of sawdust disposal and would help in conserving natural aggregate reservoirs.