Performance evaluation of concrete incorporating oat husk ash from cold regions as a supplementary cementitious material

The declining availability of conventional supplementary cementitious materials (SCMs), such as fly ash and slag, highlights the need for alternative and sustainable options to lower the carbon footprint of concrete. This study is the first to examine oat husk ash (OHA), a renewable bio-based-derived ash, as a novel SCM for partial replacement of general use (GU) and portland-limestone (GUL) cements to produce concrete. Eight concrete mixtures incorporating 20% and 30% OHA were prepared, alongside fly ash-based mixtures for comparison. Fresh properties, mechanical performance, durability (fluid absorption and salt-frost scaling), and microstructural characteristics (porosity, hydration kinetics, and microstructure) were systematically evaluated. The overall results indicated that the development of concrete prepared from binders incorporating general use and limestone cements blended with OHA is possible, as OHA mixtures achieved comparable or higher compressive strengths than references and fly ash concretes, while maintaining workability through appropriate superplasticiser dosage. Moreover, OHA-based specimens showed reduced fluid absorption, refined pore structure, and improved salt-frost scaling resistance, particularly with the GUL cement. These enhancements are attributed to OHA’s high amorphous silica content, fine particle size, and pozzolanic reactivity, which promoted paste maturity and matrix densification. The findings position OHA as a viable SCM that can contribute to decarbonizing the cement industry and produce sustainable concrete, while mitigating environmental burdens from uncontrolled biomass combustion and landfill disposal.