Aging damage model of concrete behavior during the leaching process

Abstract

This paper deals with the effect of the leaching process of cement-based materials on their mechanical properties. This process mainly induces a total leaching of Ca(OH)2 and a progressive decalcification of the C-S-H leading in turn to a gradient of C/S ratio in the leaching zone. Modeling of the deterioration of cement paste exposed to leaching consists of a decrease in the local elastic modulus with both a damage function d and an aging function L:E=E0 (1-d)(1-L). The main parameter fo the aging function is the residual calcium content in the material. This calcium content depends directly on the thickness of the degraded zone and on the different types of hydrates in the cement paste. The non-linearity of the mechanical behavior of the cement-based material is described by a damage function whose main state parameter is the equivalent strain. The characteristic parameters of the material are identified by a compressive loading test. The model of aging damage behavior proposed in this paper corresponds perfectly with the experimental results obtained in the case of a uniaxial compressive load.