Sustainable Cement Development using Sugarcane Pressmud

Abstract

The growing demand for Ordinary Portland Cement (OPC) in the construction industry continues to accelerate global carbon dioxide (CO₂) emissions, accounting for approximately 7–8% of anthropogenic greenhouse gas release. To address this environmental challenge, researchers are increasingly exploring alternative binders and supplementary cementitious materials (SCMs) derived from industrial and agricultural by-products. This study investigates sugarcane pressmud, an organic waste product from sugar manufacturing, as a potential partial replacement for OPC in mortar applications. Pressmud is produced in large quantities during the filtration and clarification stages of sugar processing and typically poses disposal problems for sugar industries. Its chemical composition, containing reactive oxides such as SiO₂, Al₂O₃, and CaO, suggests potential pozzolanic reactivity and filler activity when processed into fine powder form. In this research, mortar specimens were prepared using varying levels of pressmud replacement (0%, 5%, 7.5%, 10%, 12.5%, and 15% by mass of cement). The water-to-binder ratio and sand content were kept constant to ensure valid comparisons. Standardized testing methods following ASTM C109 were employed to determine compressive strength at 3, 7, and 28 days of curing. Additional observations were made regarding workability and setting behavior to evaluate the practical feasibility of pressmud as an SCM. Experimental results demonstrated that moderate levels of replacement (particularly 7.5–10%) provided enhanced compressive strength relative to the control mix, with a maximum improvement of about 8–9% at 28 days. The improvement is attributed to the filler effect of fine pressmud particles, microstructure densification, and potential secondary hydration reactions contributing to additional C–S–H formation. Lower density values of the pressmud mix indicate its potential suitability for lightweight construction materials. However, at higher replacement levels (above 12.5%), the dilution effect dominated, leading to reduced strength. Overall, the findings highlight that sugarcane pressmud, when used within an optimal substitution window, can serve as an eco-friendly, cost-effective, and sustainable alternative to conventional cement. The study contributes to both waste management and decarbonization strategies by demonstrating a practical pathway to reduce clinker content and mitigate environmental burdens in cement-based materials.