What is the role of polypropylene mesh fiber in concrete engineering

Polypropylene mesh fiber is made from modified polypropylene as raw material, processed through extrusion, stretching, mesh formation, surface modification treatment, short cutting and other processes. The fibers form a mesh like structure, and during the mixing process of concrete, the mesh like fibers are squeezed and torn apart into single fibers with hooks at both ends, which are distributed in multiple directions and mutually entangled, enhancing the adhesion between the fibers and the concrete. A large number of fibers are distributed in a three-dimensional state in concrete, providing a mesh like supporting effect, fundamentally changing the crack resistance, impact resistance, fatigue resistance, and wear resistance of concrete, greatly improving its toughness and deformation ability, and significantly improving the quality of concrete engineering.

Mechanism of action

During the hardening process of cement concrete, the hydration reaction between cement and water causes shrinkage of the concrete volume. In the later stage, due to the evaporation of free water in the concrete, shrinkage occurs, and these shrinkage stresses exceed the tensile strength of the cement matrix, resulting in microcracks inside the concrete. About 70% of microcrack development is completed in 3-7d gel period, when the tensile strength of concrete is less than 1MPa. After adding fibers for strong and tough series concrete mortar to concrete, the fibers can easily and quickly disperse uniformly in the concrete to form a disordered support system, dispersing the directional stress of the concrete, preventing the occurrence and development of primary cracks in the concrete, eliminating or reducing the number and scale of primary microcracks, greatly improving the crack resistance and impermeability of concrete, improving the toughness of concrete, and thus extending the service life of concrete. In addition, due to the inherent strength of fibers, the anchoring effect formed by the uniform dispersion of fibers in concrete can absorb a certain amount of destructive energy in an instant.