Physical Properties and Seepage Characteristics of Optimized Fiber-Reinforced Permeable Concrete
Fusheng Wen, Kunqiang Zhang, Fan Huafeng, Shengtong Zhai, Fusheng Liu
Abstract
Permeable concrete is required to have adequate strength, water permeability, and freeze-thaw resistance as pavement material. The purpose of this research is to improve the properties of fiber-reinforced permeable concrete (FRPC) based on orthogonal experimental design by adjusting water-cement ratio (w/c), target porosity, volume content of polyacrylonitrile fiber (PANF), and polypropylene plastic fiber (PPF). Computer tomography (CT) is applied to generate the three-dimensional (3D) pore structure model of optimized FRPC for permeability prediction and seepage flow simulation by the computed fluid dynamics (CFD) method. The results show that the FRPC with w/c of 0.37, target porosity of 20%, PANF volume content of 0.16%, and PPF volume content of 0.25% can obtain reasonable strength (compressive strength>20 MPa, flexural strength>2.5 MPa), high water permeability (permeability coefficient>20 mm/s), and adequate frost resistance (freeze-thaw cycles>200). The permeability coefficient obtained by numerical simulation shows error less than 10% in comparison with experimental results. The relationship of seepage velocity and pressure gradient confirms to Darcy-Forchheimer’s law and the critical Reynolds number for optimized FRPC with aggregate sizes of 10–15 mm is 21.92.