Utilization of waste paper pulp ash as a partial cement replacement in cement mortar: a sustainable approach

This study presents a novel approach to sustainable construction by utilizing waste paper pulp ash (WPPA) as a partial replacement for Ordinary Portland Cement (OPC) in mortar, addressing the problem of high carbon emissions and waste disposal associated with cement production. OPC was partially replaced with WPPA at 0%, 5%, 10%, 15%, and 20% by weight. The resulting mixtures were evaluated for consistency, setting time, soundness, water absorption, efflorescence, shear bond strength, flexural strength, and compressive strength. The results show that WPPA-blended mortars exhibited higher consistency and longer setting times but remained within acceptable standard limits. Water absorption slightly increased with WPPA content, while efflorescence remained minimal. The optimum replacement level was found to be 5%, producing the highest shear bond strength (0.258 MPa), flexural strength (9.1 MPa), and compressive strength (43.38 MPa) at 28 days. However, strength was decreased beyond 10% replacement due to reduced cementitious content. These findings indicate that WPPA can serve as a sustainable and eco-friendly cement substitute, contributing to resource conservation and reducing environmental impact.