Experimental study of gas diffusion in cement paste

Image analysis of cement paste: relation to diffusion transport

Decalcification shrinkage of cement paste

Decalcification of cement paste in concrete is associated with several modes of chemical degradation including leaching, carbonation and sulfate attack. The primary aim of the current study was to investigate the effects of decalcification under saturated conditions on the dimensional stability of cement paste. Thin (0.8 mm) specimens of tricalcium silicate (C3S) paste, white portland cement (W...

Experimental study of gas diffusion in a pulmonary acinus model

D. Habib, D. Grebenkov, X. Maître, L. De Rochefort, E. Durand, G. Guillot U2R2M CNRS UMR8081, Université Paris-Sud Bât.220, Orsay, France Introduction Using MRI with Hyperpolarized (HP) gases, one can measure diffusion of Helium-3 in the lungs and detect changes due to pathologies such as emphysema [1]. In vivo measurements showed deviation to a simple Gaussian behavior with a single apparent d...

Onset of cohesion in cement paste.

It is generally agreed that the cohesion of cement paste occurs through the formation of a network of nanoparticles of a calcium-silicate-hydrate ("C-S-H"). However, the mechanism by which these particles develop this cohesion has not been established. Here we propose a dielectric continuum model which includes all ionic interactions within a dispersion of C-S-H particles. It takes into account...

Drying Shrinkage Mechanisms in Portland Cement Paste

The shrinkage mechanisms of portland cement paste were investigated from shrinkage, weight loss, and pore structure measurements using nitrogen sorption and mercury intrusion porosimetry (MIP). Thin samples (2.3 mm) of well-hydrated (165 d) pastes of 0.4 and 0.6 water-to-cement (W/C) ratios were dried directly from saturated surface dry state to 75%, SO%, 11%, and 0% relative humidity (rh). Fro...