Association of macroscopic laboratory testing and micromechanics modelling for the evaluation of the poroelastic parameters of a hardened cement paste

Abstract

International audienceThe results of a macro-scale experimental study performed on a hardened class G cement paste [Ghabezloo et al. (2008) Cem. Con. Res. (38) 1424-1437] are used in association with the micromechanics modelling and homogenization technique for evaluation of the complete set of poroelastic parameters of the material. The experimental study consisted in drained, undrained and unjacketed isotropic compression tests. Analysis of the experimental results revealed that the active porosity of the studied cement paste is smaller than its total porosity. A multi-scale homogenization model, calibrated on the experimental results, is used to extrapolate the poroelastic parameters to cement pastes prepared with different water-to-cement ratio. The notion of cement paste active porosity is discussed and the poroelastic parameters of hardened cement paste for an ideal, perfectly drained condition are evaluated using the homogenization model

Effect of supercooling on the instantaneous freezing dilation of cement-based porous materials

“…In addition, such multiscale modeling has been able to predict effective mechanical properties (Ghabezloo, 2010;Pichler and Hellmich, 2011). Through nano-indentation measurements, the bulk modulus and shear modulus of C-S-H solid, the main hydration product of ordinary Portland cement (OPC), were obtained as k s = 31:8 GPa and g s = 19:1 GPa (Ulm et al, 2004).…”

Review of the study on macro-mechanical characteristics of wet concrete and their analysis methods

“…Water in the pore will cause wet concrete compressive strength decreasing compared with dry concrete [3]. Ghabezloo (2010) carried out the compression tests of mortar under water drainage and undrained, and the porous elastic parameters of grout material were evaluated with the use of multi-scale homogenization method [33]. studied the influence of porosity to the effective bulk modulus and elastic modulus of saturated concrete with three-phase sphere model and cylindrical hollow rod model, and based on the assumption that the pore water did not have shear resistance, the effective elastic modulus and Poisson's ratio of saturated concrete were gotten [34].…”

Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling

“…In this case, the chemical affinity is assumed constant, which implies A x ¼ 1 [20,21]. The stage duration, noted t 0 x , reads:…”

“…So, several homogenization modelling methods were used for predicting the elastic behaviour of cement based materials during the hardening phase [15][16][17][18][19][20][21][22], based on the knowledge of the elastic properties and volume fractions of its constituents either during the hydration or in post hydration phase. The predictive capabilities of such upscaling approaches to determine the macroscopic elastic properties seem to be well established.…”

“…So, a prediction of the properties of the cement paste from the evolution of the concentration of its constituents is clearly desirable for engineers. Such kind of prediction was already provided in the past for the prediction of mechanical properties at an early age [15][16][17][18][19][20][21]. However, these studies are restricted to a period of hydration corresponding to relatively large values of concentration of hydrates.…”