A micromechanical four-phase model to predictthe compressive failure surface of cement concrete
Journal Title: Frattura ed Integrità Strutturale - Year 2014, Vol 8, Issue 29
Abstract
In this work, a micromechanical model is used in order to predict the failure surface of cementconcrete subject to multi-axial compression. In the adopted model, the concrete material is schematised as acomposite with the following constituents: coarse aggregate (gravel), fine aggregate (sand) and cement paste.The cement paste contains some voids which grow during the loading process. In fact, the non-linear behaviorof the concrete is attributed to the creation of cracks in the cement paste; the effect of the cracks is taken intoaccount by introducing equivalent voids (inclusions with zero stiffness) in the cement paste. The three types ofinclusions (namely gravel, sand and voids) have different scales, so that the overall behavior of the concrete isobtained by the composition of three different homogenizations; in the sense that the concrete is regarded asthe homogenized material of the two-phase composite constituted of the gravel and the mortar; in turn, themortar is the homogenized material of the two-phase composite constituted of the sand inclusions and a(porous) cement paste matrix; finally, the (porous) cement paste is the homogenized material of the two-phasecomposite constituted of voids and the pure paste. The pure paste represents the cement paste before theloading process, so that it does not contain voids or other defects due to the loading process. The abovementionedthree homogenizations are realized with the predictive scheme of Mori-Tanaka in conjunction withthe Eshelby method. The adopted model can be considered an attempt to find micromechanical tools able tocapture peculiar aspects of the cement concrete in load cases of uni-axial and multi-axial compression.Attributing the non-linear behavior of concrete to the creation of equivalent voids in the cement paste providescorrespondence with many phenomenological aspects of concrete behavior. Trying to improve thiscorrespondence, the influence of the parameters of the evolution law of the equivalent voids in the cementpaste is investigated, showing how the parameters affect the uni-axial stress-strain curve and the failure surfacesin bi-axial and tri-axial compression.
Authors and Affiliations
A. Caporale, R. Luciano
Keywords
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- EP ID EP99736
- DOI 10.3221/IGF-ESIS.29.03
- Views 72
- Downloads 0
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