Sustainable Low-Carbon Cement: Performance Enhancement with Calcined Natural Pozzolans Through Compressive Strength, Porosity, and Microstructural Analysis

The global cement industry faces a critical challenge of reducing its substantial carbon footprint while maintaining material performance. Portland cement production significantly contributes to global CO₂ emissions, necessitating innovative sustainable alternatives. This study evaluates the transformative potential of calcined natural pozzolans as a strategic approach to developing low-carbon cement. By systematically investigating the effects of calcined natural pozzolans derived from kaolinite and pyroclastic rocks on cement paste properties, the research demonstrates a promising pathway to environmentally efficient cement formulations. Utilizing advanced characterization techniques including XRD, TGA, SEM-EDX, and gas adsorption porosimetry, this study provides insights into hydration kinetics, compressive strength development, microstructural evolution, and porosity refinement. The results reveal that calcined natural pozzolans strategically enhance cement performance by accelerating hydration processes, improving compressive strength, and sophisticating microstructural characteristics. Notably, pastes incorporating pyroclastic rock pozzolans exhibited superior mechanical properties, with 28-day compressive strengths exceeding ordinary Portland cement by 35.2%. These findings not only validate the technical feasibility of natural pozzolan-based low-carbon cement but also underscore their potential to meaningfully reduce the construction industry's environmental impact.