Evaluating the potential of oil seed extract ashes from niger, cotton, and flaxseed as sustainable supplementary cementitious materials

Abstract

This study evaluates the potential of oil seed extract ashes (OSAs) from niger, cotton, and flaxseed, as a supplementary cementitious material (SCM) in cement mortar applications. The pozzolanic reactivity of niger and flaxseed OSAs was assessed through compressive strength tests, with results showing 28-day strengths of 40.74 MPa and 43.36 MPa, respectively, achieving 85–90% of OPC at 48.73 MPa. Workability tests revealed slight reductions in flow diameters for niger (115 mm) and flaxseed (110 mm) OSAs compared to OPC (118 mm), indicating denser particle packing. In contrast, cotton OSA exhibited a higher flow of 140 mm. Cotton OSA lacks pozzolanic activity compared to niger and flaxseed due to the absence of CaO and Al₂O₃, along with very low SiO₂. Cost analysis demonstrated a 7.6–9.2% reduction in material costs, with niger-based mortar priced at INR 5504/m³ and flaxseed-based mortar at INR 5605/m³, compared to OPC at INR 6065/m³. CO₂ emissions were reduced by 19%, with niger and flaxseed OSA mortars emitting 401 kg CO₂/m³ and 400 kg CO₂/m³, respectively, compared to 494 kg CO₂/m³ for OPC. The microstructural characterization of these OSAs by FESEM, XRF, XRD, FTIR, Raman, and TGA confirms that these materials present viable, cost-effective, and eco-friendly alternatives to OPC as SCMs.