Performance evaluation of self-compacting concrete incorporating sunflower husk ash as a sustainable cement...

The growing demand for low-carbon construction materials has intensified research on supplementary cementitious materials (SCMs) as partial replacements for ordinary Portland Cement (OPC). While several agricultural ashes such as rice husk ash and sugarcane bagasse ash have been extensively studied, limited investigations have comprehensively examined the microstructural behavior and durability performance of sunflower husk ash (SHA) in self-compacting concrete (SCC). Addressing this research gap, the present study evaluates the performance of SCC incorporating SHA as an environmentally sustainable SHA demonstrates potential as a supplementary cementitious material that may contribute to cement reduction at replacement levels of 0%, 5%, 10%, 15%, 20%, and 25%. Fresh properties were assessed using slump flow, T₅₀ time, and V-funnel tests. Mechanical performance was evaluated through compressive, split tensile, and flexural strength tests at 7 and 28 days. Durability performance was determined using water absorption and rapid chloride penetration tests (RCPT). Microstructural characterization was conducted using SEM, EDAX, FTIR, and XRD analyses to investigate phase development and hydration mechanisms. The results indicate that 20% SHA replacement yields the highest performance among the tested mixes balance of workability, strength, and durability, achieving a 28-day compressive strength of 53.0 MPa, split tensile strength of 4.7 MPa, and flexural strength of 6.5 MPa, along with reduced water absorption and chloride ion permeability. Beyond 20% replacement, performance declined due to dilution of cementitious phases. The findings establish SHA as a viable supplementary cementitious material for high-performance SCC, offering a sustainable pathway for reducing OPC consumption, particularly in regions with abundant sunflower waste.