Advancing Eco-Friendly Concrete with Locally Sourced Natural Pozzolana

Waleed H Khushefati¹Ayman Shihata¹Ahmed, Elwy¹RAMAZAN DEMIRBOGA^2*

• ¹King Abdulaziz University Faculty of Engineering, Jeddah, Saudi Arabia
• ²Alfaisal University College of Engineering, Riyadh, Saudi Arabia

This study comprehensively investigates the potential of locally sourced Natural Pozzolana (NP) from Saudi Arabia to develop sustainable green concrete. An extensive experimental program was conducted, involving the development of nine concrete mixes with over 450 samples, replacing partially the Ordinary Portland Cement (OPC) with NP at varying percentages (up to 50%) as Supplementary Cementitious Materials (SCMs) and the supplementary addition of Silica Fume (SF) and corrosion inhibitors (INH). Fresh concrete properties (slump and initial temperature) and mechanical properties (compressive and splitting tensile strength at 7, 28, 56, 90, and 180 days) were evaluated. Durability was assessed through chloride penetration and sulphate resistance tests. The results show that although high NP contents reduce early-age mechanical strength, all NP blends exhibit substantial long-term strength recovery, with NP20–NP30 achieving 94–100% of the control strength at 90 to 180 days due to sustained pozzolanic reactivity. Durability performance improved across all binders: NP mixes reduced chloride permeability by 40–50%, while SF–NP and INH-containing systems achieved 70–76% reductions, shifting their RCPT classification from "moderate" to "very low." Sulphate exposure likewise produced strength-retention ratios of 100–114%, confirming stable performance with no deterioration up to 180 days. All trends were statistically validated through one-way ANOVA, confirming that the improvements are significant and attributable to binder composition. These findings highlight the potential of using locally sourced NP to produce sustainable concrete, reduce carbon emissions, and support Saudi Arabia's Vision 2030 for sustainable development.