Research progress on the effect of fiber on early-age shrinkage and cracking of concrete

Concrete durability is critical to structural safety and service life, yet early-age shrinkage cracking significantly compromises long-term durability. To address this, fiber-reinforced concrete has emerged as an effective solution. This paper reviews the effects of fibers on early-age shrinkage and cracking in concrete. It elaborates on the principal mechanisms of shrinkage and analyzes the evolution of cracks from a multiscale perspective. This paper summarizes the properties of organic fibers, inorganic fibers, and other fiber types, and analyzes their respective effects and mechanisms in inhibiting early-age shrinkage cracking in concrete. The review indicates that fibers mitigate shrinkage-induced cracking through physical mechanisms such as crack bridging, microcrack blocking, and stress redistribution. Furthermore, by analyzing parameters such as fiber dosage, length, and diameter, recommended ranges for key fiber parameters are provided. This paper provides a theoretical basis for understanding early-age fiber-reinforced concrete behavior and supports material selection and crack-resistant design in engineering applications.