Enhancing the mechanical properties of sawdust concrete with silica fume, metakaolin, and marble powder

Abstract

This research explores the innovative use of sawdust as a sustainable aggregate in concrete, addressing both environmental and structural challenges. The study investigates the effects of incorporating sawdust at varying proportions (15%, 25%, and 35%) into concrete mixtures, aiming to reduce carbon emissions and promote lightweight construction. Recognizing the negative impact of waste glass powder on concrete strength, this research introduces silica fume (SF), metakaolin (MK), and marble powder (MP) as potential additives to enhance the compressive strength and reduce the specific weight of sawdust concrete. The experimental program involved 13 concrete mixtures, with SF, MK, and MP added at 5%, 10%, and 15% by mass to a 25% sawdust mix. Results indicate that increasing sawdust content significantly decreases compressive strength, with reductions from 31.655 MPa in the control to 6.291 MPa at 35% sawdust. However, the addition of SF and MK notably improved strength, with SF enhancing it by 68.8% at 10% addition and MK by 69.3% at 5%. MP, while less effective, still increased strength by 42.9%. Sawdust addition consistently reduced concrete density, from 2399 kg/m³ in the control to 2091 kg/m³ at 35% sawdust. SF further reduced density, whereas MK and MP increased it. The study concludes that 10% SF or 5% MK are optimal for improving sawdust concrete properties, offering a balance of enhanced strength and reduced weight. This research contributes to sustainable construction practices by demonstrating the viability of sawdust and specific additives in creating environmentally friendly, lightweight concrete solutions.