Cow Dung Ash in Mortar: An Experimental Study

Abstract

This study investigated the impact of using cow dung ash (CDA) as a partial replacement for ordinary Portland cement (OPC) in mortar. Mortar mixes are prepared by replacing OPC with CDA at varying levels: 5%, 10%, 15%, 20%, 25%, and 30%. The chemical composition of CDA shows that it is composed primarily of SiO2, Al2O3, and Fe2O3, with a significant amount of loss of ignition. The workability, hardened properties, and microstructure of CDA-containing mortars are also analyzed. The increasing CDA content in mortar reduces workability and, beyond 5%, it causes high water absorption due to CDA’s porous nature and unremoved organic compounds. This impacts the density and compressive strength of the hardened mortar as well as compromising its homogeneous characteristics. When using 5% CDA, the bulk density and compressive strength of the mortar are comparable to those of the control mixes. Nonetheless, as the proportion of CDA increases, both the bulk density and compressive strength of the mortar diminish. The thermal stability of mortar mixes with 10%, 20%, and 30% CDA is unaffected at temperatures between 500 °C and 600 °C. The Fourier-transform infrared spectroscopy (FTIR) analysis reveals the presence of unreacted particles and wide stretched C–S–H gels in the mortar samples. In general, the results suggest that CDA can be utilized as a substitute for OPC at a ratio of up to 10% in the manufacturing of mortar and can serve as a feasible alternative cementitious material.

Keywords

• cow dung ash
• mortar
• microstructure
• workability
• durability
• sustainability