Multiscale Modeling of Fracture Processes for Hardened Cement Paste

Abstract

The paper studies the fracture processes of hardened cement paste and its mechanical performance through a multiscale lattice fracture model. The fracture process of cement paste is modeled at microscale and mesoscale respectively, and the bridge between these two scales is established by employing a parameters passing scheme. The shape of cement paste specimen is cube, and its side length is 100 μm in the microscale model and 1 mm in the mesoscale model. The corresponding mesh sizes for these two scales are 1 μm and 0.1 mm respectively. Hence, the length 100 μm is the point which connects microscale model to mesoscale model. At microscale the spheres based model is employed to represent the microstructure of hardened cement paste, but at mesoscale the cement paste is modeled as continuum material with some heterogeneity, which is implemented during the lattice network construction by introducing some geometry randomness. It is assumed that the cement paste material behaves linear-brittle locally at microscale, while some softening is allowed locally at mesoscale and is determined by the output of the microscale model. A numerical experiment of uniaxial tensile test is presented to illustrate the modeling procedures and the parameters passing scheme.