Performance appraisal of high volume of sustainable unprocessed eco-minerals, ground and unground eco-processed pozzolan as cement replacement materials in mortar

Abstract

This research aims to develop sustainable and structural-grade mortar by partially replacing conventional cement with two palm oil-based by-products namely, unprocessed eco-minerals (UEM), ground and unground eco-processed pozzolan (GEPP & EPP). The study investigated the physical, chemical, morphological, and mineralogical properties of UEM, EPP, and ground EPP. In addition, this research focused on examining the effect of cement replaced by UEM, EPP, and GEPP at various levels on workability, hardened properties, microstructure, and CO2 emissions aspects of mortar in two stages. Cement substituted by UEM and EPP at 0–70% in first stage, while it replaced by EPP and GEPP at 0–50% in second stage. The research findings demonstrate that incorporating UEM, EPP, and GEPP as SCMs reduces the flow, density, UPV, and compressive strength compared to the control mortar while increasing the water absorption and porosity. The quality of mortar containing up to 30% UEM and 70% EPP is classified as good based on the UPV results. The 30% UEM, 50% EPP, and 50% GEPP mortar are classified as structural-grade mortar. The control mortar exhibited a denser matrix when compared to UEM, EPP, and GEPP mortars from FESEM images. GEPP consumed the highest amount of Ca(OH)2, followed by EPP and UEM based on the XRD pattern. Incorporating UEM and EPP significantly reduces CO2 emissions compared to control mortar. Moreover, this research promotes the acceptance and utilisation of EPP in the construction industry.