Enhancing the Activation of Saudi Natural Pozzolan Using Thermal, Mechanical, Chemical, and Hybrid Treatment Approaches

Saudi Natural Pozzolan (SNP) can be processed and used in construction as a partial replacement for Ordinary Portland Cement (OPC). Its use as a supplementary cementitious material supports more sustainable and eco-friendly building practices. This study investigates various treatment methods for enhancing the reactivity of SNPs, including thermal, mechanical, thermo-mechanical, mechano-thermal, and chemical techniques. The activity of 18 different treated SNP mixtures was evaluated using the Strength Activity Index (SAI). Results identified the optimum conditions for each treatment: thermal treatment at 600 °C, mechanical treatment through 6 h of grinding, and chemical treatment with a 9% addition of hydrated lime. The SAI results demonstrated that a 6 h mechanical treatment was the most effective method for activating the raw pozzolan. X-ray diffraction (XRD) analysis revealed that phases such as quartz, anorthite, and aluminate are significant contributors to pozzolanic activity. The XRD analysis was further supported by scanning electron microscopy (SEM), which examined microstructural changes. This study highlights the potential of maximizing the utilization of extensive pozzolan resources in the Harrat region of the Kingdom of Saudi Arabia. Treated SNP can be applied in various industries, such as mining backfills, brick industry, and pozzolanic concrete, as a sustainable and environmentally friendly material.