Multi-scale and multi-physics numerical modeling of concrete

Giovanni Di Luzio

This seminar deals with important issue of the aging and deterioration of concrete structures. The assessment and the future predictions of those deteriorated structures can be only based on physically sound computational models that are rigorously validated. In this contest a multi-scale and multiphysics numerical framework is presented with reference to two different applications: self-desiccation and Alkali Silica Reaction (ASR) in concrete.
The numerical simulations of self-desiccation are carried out using a novel approach which consists in combing a cement hydration model at the microstructural level, the CEMHYD3D model, to a macroscopic hygro-thermo-chemical (HTC) model. The multi-scale coupling between the two models is performed in order to identify the parameters of the HTC formulation.
ASR is a slow deterioration process that develops over years to decades and it is influenced by changes in environmental and loading conditions of the structure. A multi-physics formulation is used to compute the evolution of temperature, humidity, cement hydration, and ASR in both space and time, which is then used within physics-based formulations of cracking, creep and shrinkage that are modeled within the framework of a discrete model, the Lattice Discrete Particle Model (LDPM). The overall model is calibrated and validated on the basis of experimental data available in the literature.