Measuring and computational modeling of liquid transfer in fractured concrete

Cracks in concrete are measured in 3D by microfocus X-ray computer tomography. A methodology to convert 3D measured crack data into a network of tubes, which offers the possibility to calculate liquid filling and the permeability, is presented. A numerical model for unsaturated moisture transport in fractured porous media is developed. The model combines a discrete fracture model for moisture flow in a variable aperture fracture with a finite element model for unsaturated flow in the porous matrix. To achieve a stable numerical solution, movable nodes, following the moisture front in the fracture, are introduced at the boundary of the finite element mesh. The model is validated with simulations of water infiltration in fractured brick samples as monitored with X-ray radiography.