Fiber-synergistically reinforced MICP sand-fixing materials: mechanisms, performances and prospects for bionic design

Traditional microbially induced calcium carbonate precipitation (MICP) technology inherently suffers from high brittleness of cementitious products and poor environmental tolerance when applied to desert soil solidification. To address these drawbacks, this review proposed the construction of a novel fiber-coupled biomineral composite material by introducing fibrous materials. From the perspective of materials science, the research progress of fiber-synergized MICP desert soil solidification materials was systematically summarized, with a focus on analyzing the core synergistic reinforcement mechanisms of such composite materials. The results indicated that fibers effectively inhibited crack propagation through physical bridging effects, transforming the material failure mode from brittle to ductile, with the residual strength improved by up to 300%. Fibers provided abundant colonization sites for microorganisms, prolonged their metabolic activity and significantly enhanced mineralization efficiency. In addition, the fiber surface induced heterogeneous nucleation of calcium carbonate, regulated crystal orientation and spatial distribution, and formed a multi-component cementation and solidification unit consisting of fibers, mineralized shells and sand particles, which greatly improved the interface bonding strength. On this basis, drawing on the interface regulation strategies of natural biomineral materials, methods such as bionic adhesion interface design and template-induced crystal form regulation were proposed. Facing the dynamic changes of desert environments, the feasible approaches for developing intelligent fiber and cementing solution systems with environmental perception and response capabilities were further discussed. Moreover, prospective key research directions in the future were put forward, including bionic mineralization interface design, development of environment-adaptive intelligent fibers, and construction of multi-field coupled numerical models. This review aims to provide systematic insights and framework guidance for interdisciplinary research in the fields of engineering geology, environmental geotechnical engineering and ecological restoration.