Poromechanical behaviour of hardened cement paste under isotropic loading

TL;DR

This study investigates the poromechanical behavior of hardened cement paste under isotropic loading through experiments and modeling, revealing microcracking and property degradation consistent with porous media theory.

Contribution

It provides experimental determination of poroelastic parameters and discusses effective stress laws for cement paste under isotropic stress.

Findings

Elastic property degradation due to microcracking

Determined poroelastic parameters consistent with porous media theory

Effective stress laws govern volume and porosity evolution

Abstract

The poromechanical behaviour of hardened cement paste under isotropic loading is studied on the basis of an experimental testing program of drained, undrained and unjacketed compression tests. The macroscopic behaviour of the material is described in the framework of the mechanics of porous media. The poroelastic parameters of the material are determined and the effect of stress and pore pressure on them is evaluated. Appropriate effective stress laws which control the evolution of total volume, pore volume, solid volume, porosity and drained bulk modulus are discussed. A phenomenon of degradation of elastic properties is observed in the test results. The microscopic observations showed that this degradation is caused by the microcracking of the material under isotropic loading. The good compatibility and the consistency of the obtained poromechanical parameters demonstrate that the behaviour of the hardened cement paste can be indeed described within the framework of the theory of porous media.