Early-age strains and stresses in bi-axially restrained expansive concrete elements

Abstract

Practical application of expansive concretes in reinforced concrete structures needs the rational design model for assessment the early-age stress-strain parameters of self-stressing concrete elements under any restraint conditions during the expansion stage. Various strategies are used to calculate the restrained expansion strains and self-stresses but, in most cases, disregarding the elastic-plastic behaviour of expansive concrete at early ages. It’s noticeable that in case of bi-axial restraint conditions both the elastic-plastic parameters of expansive concrete and the influence of restraint in orthogonal directions should be taken into consideration. To achieve a reliable solution a design model for estimation the restrained expansion strains and self-stresses in self-stressed structural elements under bi-axial restraint conditions (2D MSDM) at expansion stage has been developed. The proposed design model is based on the MSDM for the case of uniaxial restraint arrangement. The validation of 2D MSDM was confirmed by the experimental results of expansive concrete elements under 2D confinement carried out by authors as well as obtained by other researchers.