Plant fiber microcapsules for controlling hydration heat and cracking in cement-based materials: A comprehensive review

Thermal cracking induced by cement hydration heat poses a significant threat to the durability of mass concrete structures. This review comprehensively assesses the potential of Plant Fiber Microcapsules (PFMs) as a novel and sustainable solution for this longstanding issue. PFMs are engineered with a unique core–shell structure, utilizing renewable plant fibers (rich in retarding sugars) as the core and paraffin as the protective shell. We critically analyze the synthesis protocols, microstructure, and key properties of PFMs, demonstrating their exceptional efficacy in regulating cement hydration. The incorporation of PFMs achieves a remarkable reduction of over 40% in the peak heat release rate and significantly lowers the overall temperature rise in concrete, directly mitigating thermal stress. The high performance is attributed to a synergistic “Barrier-Release-Retard-Buffer” mechanism, which integrates physical encapsulation, controlled chemical retardation, and phase-change thermal buffering. With compelling advantages in cost-effectiveness, environmental friendliness, and performance, PFMs emerge as a highly promising material technology for developing sustainable and crack-resistant concrete, offering a practical pathway towards greener construction.