Steel fiber reinforced LC3 subject to microwave curing: evolution of hydration microstructure and optimization of thermal homogeneity

Abstract

Microwave curing technology has garnered considerable attention in cement material processing. However, issues, such as non-uniform heating and sluggish temperature escalation, persist. To this gap, this study introduces an innovative approach to enhance microwave heating efficiency in the low-carbon LC³ through the strategic incorporation of steel fibers. Heat conduction pathways is optimized via appropriately controlled content of steel fibers. Experimental results reveal that increasing steel fiber content to 3 vol% significantly accelerates heating rate of LC³, achieving an average increment of 0.286 °C/s, while remarkably improving heating uniformity. Furthermore, microwave curing substantially enhances the mechanical properties of LC³. Comparative analysis with standard curing method demonstrates notable compressive strength enhancements up to 36.1 % and 37.3 % for specimens with 2 % and 3 vol% steel fiber contents, respectively. The microwave curing process promotes hydration reactions, yielding homogeneous product distribution and reduced porosity. These findings provide valuable insights into the thermal effects of steel fiber incorporation in microwave-cured LC³, offering theoretical framework for optimized dosage strategies and quantitative process control. This research underscores the innovation and practical significance of microwave curing technology in advancing sustainable cementitious material processing.