Eco-Sustainable Cement: Natural Volcanic Tuffs’ Impact on Concrete Strength and Durability

Abstract

This study underscores the potential of utilizing natural volcanic tuffs (NVTs) as supplementary cementitious materials (SCMs) in alignment with global sustainability efforts aimed at mitigating the cement industry’s negative impacts on both the economy and the environment. Experimental investigations were conducted on concrete mixtures containing 10%, 20%, 30%, 40%, and 50% NVT as partial cement replacements to assess their influence on concrete’s mechanical and microstructural properties. Based on the findings, concrete samples with 10% NVT replacements exhibited increased flexural and compressive strengths of 35.6% and 5.6%, respectively, compared with ordinary concrete after 28 days. The depth of water penetration in the concrete samples was significantly reduced by the inclusion of NVT, with a maximum reduction of 56.5%. Microstructural analysis using scanning electron microscopy (SEM) revealed enhanced densification of the concrete microstructures, attributed to the high pozzolanic activity of NVT use in cement-based composites. Analysis of variance (ANOVA) revealed statistically significant relationships between NVT content and both the compressive and flexural strengths of the concrete samples. In conclusion, substituting 10% cement with NVT not only enhances the mechanical properties of concrete but also decreases the energy demand for cement production and reduces carbon dioxide (CO2) emissions, thus contributing to more sustainable construction practices.

Keywords

• natural volcanic tuffs
• cement replacement
• strength
• permeability
• microstructural analysis