Sustainable utilization of corn husk ash as a pozzolanic cement substitute for mortar production
Behailu Zerihun Hailemariam, Mitiku Damtie Yehualaw, Woubishet Zewdu Taffese, Duy‐Hai Vo
Abstract
In response to the global demand for low-carbon, energy-efficient, and sustainable construction materials, this study investigates the potential of corn husk ash (CHA) as a viable supplementary cementitious material (SCM) for partial cement replacement in mortar. CHA, derived from agricultural waste, was incorporated at 0–25 % replacement levels by weight of cement and thoroughly characterized for its chemical, physical, and mineralogical properties. With a combined SiO₂, Al₂O₃, and Fe₂O₃ content of 76.67 %, CHA satisfies ASTM Class N pozzolan requirements, demonstrating high pozzolanic reactivity. Although higher CHA content reduced workability—requiring 22 % more water and resulting in a 21 % slump reduction at 25 % replacement—significant improvements in long-term performance were observed. At 20 % CHA, the mortar achieved a dry density of 1908.84 kg/m³ , 38.32 MPa compressive strength, and 4.38 km/s ultrasonic pulse velocity after 56 days. Durability was enhanced through reduced drying shrinkage, lower water absorption, improved acid resistance, and increased surface resistivity. Microstructural analysis revealed a denser matrix with refined pores, attributed to additional C–S–H formation via pozzolanic reactions. These results highlight CHA’s potential as an eco-efficient alternative to cement, promoting greener construction. Further studies are recommended to explore its application in alkali-activated and geopolymer systems for broader structural use.