Feasibility on diverse biochars as supplementary cementitious materials

This paper investigates the feasibility of using Korean-produced biochar derived from wood (WB), rice husk (HB), and poultry manure (MB) as a cement replacement in mortar. The physicochemical and microstructural characteristics of each biochar were analyzed, and mortar specimens containing 5% biochar were tested for flow and compressive strength. WB and HB showed favorable particle sizes and large specific surface areas, enhancing internal curing and filler effects, which resulted in up to 29% higher compressive strength than plain mortar at 28 days. In contrast, MB, with coarse particles and low surface area, improved flowability but significantly reduced compressive strength by about 44%. Analytical results confirmed that WB and HB have higher carbon content and chemical stability than MB. These results demonstrate that feedstock type and physicochemical properties affect mortar performance. WB and HB showed potential for use as supplementary cementitious materials based on their strength and workability performance, whereas MB was shown to be unsuitable due to its inferior properties.