Influence of slag composition and temperature on the hydration and microstructure of slag blended cements

GGBS is used extensively as a cement replacement material, reducing the carbon footprint of cement while potentially improving technical performance. However, standards consider hydration of slag composite cements only at 20°C. This may not be applicable for use in tropical climates. This work has investigated the impact of GGBS composition and curing temperature on the hydration, microstructure and subsequent transport properties of slag blended cements. Experimental methods included calorimetry to measure heat flow during hydration, and microscopic techniques to analyze microstructural development. Results indicated significant variations in hydration kinetics and microstructural characteristics depending on both the composition of the slag and the curing temperature. Higher temperatures accelerated hydration, leading to a more refined microstructure and improved performance properties in the cement blends. The findings underscore the necessity for revising existing standards, emphasizing the importance of evaluating hydration behaviors under varied environmental conditions to ensure optimal performance of slag-based cements in diverse climates. The study provides valuable insights for materials science, particularly in enhancing the sustainability and efficacy of construction materials in changing global climates.