A numerical model for early age concrete behavior

In this paper, a new constitutive model for early age concrete mechanical behavior is presented. This model, which amalgamates the microplane model and the solidification-microprestress theory, takes into account all the major aspects of concrete behavior, such as creep, shrinkage, thermal deformation, and cracking starting from the initial stages of its maturing up to the age of several years. The aging viscoelastic behavior is described according to the solidification-microprestress theory. Cracking behavior is modeled through an age-dependent microplane model, in which the free parameters are assumed to be functions of an aging variable whose evolution depends on hydration degree and temperature. Calibration and validation of the model is performed by simulating numerically the age-dependent response of sealed and unsealed specimens subject to sustained loads and/or shrinkage. The numerical simulations show that the model can reproduce the interplay between shrinkage, creep, and cracking phenomena during maturing and drying processes.