Approaches of concrete creep using mesomechanics: numerical simulation and predictive model

Abstract

Simulation and prediction of fully-aggregated concrete creep is a fairly crucial but complex task in civil engineering and material science due to the heterogeneity of concrete with mixture compositions. To investigate the contribution of each composition to the concrete creep and the relationship between the basic creep laws of concrete and mortar, a numerical concrete (NC) model on meso-scale is established with a 3D finite element algorithm taking into account aggregates, mortar matrix and the interfacial transition zone (ITZ). This NC model can emulate the complex mesostructure of concrete and calculate its creep by recurrence formulas without recording the history of stress in terms of the elastic aging creep theory. After being validated by existing laboratory experimental data, the proposed model is further employed to study the influential factors such as the content and elastic modulus of aggregate as well as the action of aggregates and mortar matrix via ITZ. Based on the numerical simulations and theoretical analysis, a new predictive model of concrete creep is finally proposed which is able to well interpret the dilution and restraint effects of aggregate and the interaction among compositions.