Moisture Transport and Shrinkage in Concrete at early Age

Abstract

Abstract: The moisture flow and drying of porous media, such as concrete, is tackled through the Navier-Stokes equation, where the Navier-Stokes equation is considered as the link between the theory of fluid flow, Acoustic Emission (AE) experiments on cracking (sound propagation based on the wave equation) and Lattice Gas Automata, (LGA) being a numerical simulation of the Navier-Stokes equation. Early age cracking in the ITZ is induced by using the moisture flow as the only “load” that causes cracking due to drying shrinkage volume changes in Environmental Scanning Electron Microscopy (ESEM) tests. An attempt is made to link and compare experimental results conducted by means of AE and ESEM to the results of 2-D LGA numerical simulation. Lattice Gas Automata (FHP model) is used as a basis to generate a new model for drying of porous medium. Special emphasis in a model creation is given to the Interface Transition Zone (ITZ), between aggregate and cement paste, because of the early crack initiation in this highly porous and strength-weak zone.