Investigation of the Age-Dependent Constitutive Relations of Mortar

Abstract

The stress-strain relation of cement binder is age-dependent and so is the behavior of mortar. In this study, we conducted a concurrent experimental and theoretical investigation into the effect of material age on the properties of both cement binder and mortar. First the stress-strain curves of the binder were measured over a wide range of aging time from 7 days to 18 months. Two types of binder—one with the cement paste alone and the other with the fly ash/cement combination—were chosen in the tests. The test results were simulated with a modified, age-dependent Burgers rheological model. Then measured were the stress-strain curves of the mortar that contains the same types of cement at three levels of aggregate volume concentrations: