Publication

INFLUENCE OF POROSITY AND WATER CONTENT ON THE DIFFUSIVITY OF CO2 AND O2 THROUGH HYDRATED CEMENT PASTE

Yves Houst
1994
Journal Articles

Abstract

Knowledge of the diffusivity of CO2 and 02 is of considerable importance for a quantitative assessment of the carbonation and corrosion of the reinforcement in concrete. A special measuring cell which allows the simultaneous determination of the effective diffusion coefficients of the two gases as a function of the relative humidity has been developed. Measurements have been carded out on carbonated discs of hydrated cement paste prepared with water/cement ratios between 0.4 and 0.8. The results show that, if the water/cement ratio is increased from 0.4 to 0.8, diffusion coefficients increase more than ten times. On the other hand, only little influence of the relative humidity between 50-90% the diffusivity has been observed on samples in adsorption equilibrium. The variation of diffusivity as a function of water content and porosity is explained by the characteristic microstructure, which has been characterized by water adsorption isotherms and mercury intrusion porosimetry measurements. Finally, a model with two levels in the microstructure is proposed to describe CO2 diffusion in a carbonating material.

Official source

https://infoscience.epfl.ch/entities/publication/fb8312e7-09a1-473e-a1c5-ba30fdf1baaa

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Yves Houst
1994
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/fb8312e7-09a1-473e-a1c5-ba30fdf1baaa

About this result

Related concepts (22)

Cement

A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.

Portland cement

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available.

Diffusion

Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. Diffusion is a stochastic process due to the inherent randomness of the diffusing entity and can be used to model many real-life stochastic scenarios.

Related publications (31)

Multilayer diffusion-barrier composites based on microfibrillated cellulose from wood, bacterial and algae sources

Aigoul Schreier

This work is driven by the effort towards increased environmental sustainability and aims to develop a new food packaging material based on renewable materials, and more specifically cellulose as the most abundant biomass resource on Earth. Focus was on mi ...

EPFL2024

In-Situ FTIR and Laser Induced Fluorescence RONS Characterization of Atmospheric Pressure Nanosecond-Pulsed Surface DBD Plasma for Indirect Treatments of E. Coli

Ivo Furno, Fabio Avino, Lorenzo Ibba, Rita Agus

We study the bactericidal efficacy of surface dielectric barrier discharge low-temperature plasma treatments, powered by nanosecond high voltage pulses. We achieve similar to 4-log reduction in Escherichia coli population, after 10 min treatments, at a dis ...

Springer2024

Contradict mechanism of long-term magnesium and sodium sulfate attacks of nano silica-modified cement mortars - Experimental and thermodynamic modeling

Qiao Wang

The mechanisms of external sulfate attack on cement mortars containing nano silica have been studied under full immersion conditions after 3 years. The sulfate degradation processes were compared between sodium sulfate and magnesium sulfate solutions with ...

Elsevier Sci Ltd2024