A study of the water vapor sorption isotherms of hardened cement pastes: Possible pore structure changes at low relative humidity and the impact of temperature on isotherms

Wu, Min; Johannesson, Björn

doi:10.1016/j.cemconres.2013.11.008

Cited by 60 publications

(27 citation statements)

References 20 publications

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“…That is why, as it has been mentioned in the Introduction, these two methods were not developed for this purpose unless one has enough data in hand. Note that novel experimental devices can help to obtain the required sorption data in a short time, such as using dynamic vapour sorption (DVS) to determine both sorption isotherms and drying kinetics [69,70,71,72]. If a few millimeters thickness specimens can be prepared with the well controlled geometry, the mass loss curve which is necessary for the determination of the sorption isotherm can reach a plateau in several days, which significantly reduce the time compared to the traditional saturated salt solution method.…”

Section: Knudsen Diffusion Effect On X Dmentioning

confidence: 99%

Investigation of moisture transport properties of cementitious materials

Zhang

Thiéry

Baroghel-Bouny

2016

Cement and Concrete Research

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Moisture transport in cementitious materials is directly related to the durability of concrete structures. When the material loses moisture, the drying shrinkage induces cracks which are harmful to the solid body. When liquid moves into the material, it can carry aggressive ions. Hence, moisture transport properties are important to cope with durability issues. The present paper is focused on two ways to enhance our understanding of moisture transport properties of cementitious materials. They are based on the indirect determination of the liquid water permeability and water vapour diffusion coefficient. The first one is known as the "inverse analysis" method. In a moisture transport model, the liquid permeability and diffusion coefficient can be adjusted in order to fit the measured mass loss curves and water content profiles. In the second way, measured apparent diffusion coefficient (also called moisture diffusivity) curves are fitted over a large range of relative humidity (RH) by a general expression which includes both liquid transport and vapour diffusion. Due to different RH ranges of predominance of liquid and vapour transport, the liquid water permeability and vapour diffusion coefficient can be determined separately. Input experimental data on cement pastes are collected from the literature. Discussions on relative permeability and Knudsen diffusion show a significant influence on modelling of moisture transport. A further comparison with measured permeability data is able to provide a better understanding of moisture transport properties.

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Section: Knudsen Diffusion Effect On X Dmentioning

confidence: 99%

Investigation of moisture transport properties of cementitious materials

Zhang

Thiéry

Baroghel-Bouny

2016

Cement and Concrete Research

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“…In these areas it has been proven that the use of sorption balance is able to obtain similar results to other common techniques (Johannesson and Janz 2002;Arlabosse et al 2003;Fei et al 2006). Over the last 10 years, sorption balances have been put to use more and more for cementitious materials (Anderberg and Wadsö 2008;Johannesson and Utgenannt 2001;Johannesson 2002;Robens et al 2002;Espinosa and Franke 2006;Åhs 2008;Scheffler et al 2009;De Belie et al 2010;Maruyama 2010;Dubina et al 2011;Pavlík et al 2012;Dubina et al 2014;Saeidpour and Wadsö 2015;Jennings et al 2015;M. Wu et al 2014;Kumar et al 2014;Snoeck et al 2014;Baquerizo et al 2016;Aktas et al 2015;Maruyama et al 2015).…”

Section: Introductionmentioning

confidence: 83%

The Use of Sorption Balance for the Characterization of the Water Retention Curve of Cement-Based Materials

Poyet

Trentin

Amblard

2016

ACT

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Among the necessary data in the description of the transport of water, the retention curve is a vital piece of information whose characterization can turn out to be long and fastidious. Within this framework, sorption balance is being put to use more and more often in laboratories. These experimental devices enable a faster onset for water balance using small amounts of substances previously reduced to powder. This approach proves to be particularly adapted to homogenous materials (cement pastes generally) but not to concrete because of the presence of aggregate. This article, first of all, clarifies in a summarized manner the working of sorption balance based on the results obtained with cement pastes. Secondly, a simplified method is proposed to test concrete.

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“…The same is however not true for C > 6. The temperature affects the water physical properties (density and surface tension) (Wu et al, 2014) and causes the coarsening of the pore structure in relation to Ettringite dissolution and C-S-H alteration (Brue et al, 2012). The XRD patterns of RAP+20%FA blend in Fig.…”

Section: Mineralogical and Microstructural Changesmentioning

confidence: 99%

Wetting and Drying Characteristics of Recycled Asphalt Pavement-Fly Ash Blend as a Sustainable Pavement Material

Hoy¹,

Horpibulsuk²,

Rachan³

et al. 2017

dtmse

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ABSTRACT:The usage of Recycled Asphalt Pavement (RAP) and Fly Ash (FA) blend in pavement applications contributes to the sustainable usage of such waste by-products. Although RAP-FA blend has been proven as a pavement material based on strength and leachate requirement, the durability of this blend when exposed to an aggressive environment has not been investigated to date. This research presents the effect of wetting-drying (w-d) cycles on the strength and microstructural changes of RAP-FA blend. The strength characteristic of this material was determined by Unconfined Compression Strength (UCS) test. The mineralogical and microstructural changes of the compound pavement material were also analyzed using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Test results show that the UCS of RAP-FA blend increases with increasing the number of w-d cycles (C), reaching its peak at 6 w-d cycles. The XRD and SEM analyses indicate that the increased UCS of RAP-FA blend is due to stimulation of the chemical reaction between the high amount of Calcium in RAP and the high amount of Silica and Alumina in FA during w-d cycles leading to production of more Calcium Silicate Hydrate (C-S-H) and Calcium Aluminate Hydrate (C-A-H). For C > 6, the significant macro-cracks due to the loss of moisture content during drying stage cause strength reduction. However, its reduced UCS is still greater than the minimum strength requirement even at C = 20. The outcome from this research confirms the viability of using RAP-FA blends as an alternative sustainable pavement material.

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A study of the water vapor sorption isotherms of hardened cement pastes: Possible pore structure changes at low relative humidity and the impact of temperature on isotherms

Cited by 60 publications

References 20 publications

Investigation of moisture transport properties of cementitious materials

Investigation of moisture transport properties of cementitious materials

The Use of Sorption Balance for the Characterization of the Water Retention Curve of Cement-Based Materials

Wetting and Drying Characteristics of Recycled Asphalt Pavement-Fly Ash Blend as a Sustainable Pavement Material

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