Effect of temperature on the water retention properties of two high performance concretes

Brue, Flore; Davy, Catherine; Skoczylas, Frédéric; Burlion, Nicolas; Bourbon, Xavier

doi:10.1016/j.cemconres.2011.11.005

Cited by 79 publications

(63 citation statements)

References 38 publications

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“…Carlier and Burlion (2011) carried out evaporation tests in concrete under isothermal conditions, so as to obtain its retention curve and relative permeability parameters improving the van Genuchten-Mualem's equations. Brue et al (2012) estimated desorption isotherms experimentally at different temperatures, by using a model based on Kelvin-Laplace's capillary law. Chen et al (2012) obtained water retention properties and a relative gas permeability curve in concrete by studying the effect of water saturation on gas relative permeability.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Concrete by Calibrating Thermo-Hydraulic Multiphase Flow Models

2015

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Evaporation tests in concrete columns have been analysed by numerical models to characterize the thermo-hydraulic properties and the processes in concrete. Two evaporation tests were performed; a column heated by a lamp and a column kept in room conditions. The conceptual model considers unsaturated liquid flow and transport of vapour and energy. We also calculated models that take into account the dissolved salts to study its effect on vapour pressure and evaporation. A retention curve has been obtained from relative humidity and gravimetric water content measured after dismantling the tests. The models have been calibrated by adjusting the model's results to the measured data of water loss, relative humidity and temperature inside the concrete. The parameters obtained with the calibration are the permeability, thermal conductivity, boundary conditions and a tortuosity factor for vapour diffusion. Results show that the vapour diffusion is the dominant water transport process above an evaporation front, and liquid advection is dominant below it.Keywords drying · retention curve · permeability · concrete · modelling Concrete allows building a large number of architecture and engineering structures. List of symbols 3The majority of them are exposed to alternating dry and wet conditions affecting 4 their durability. Thermo-hydraulic processes such as flow of liquid and gas in unsatu-5 rated conditions, transport of heat, vapour and dissolved salts, and evaporation and 6 condensation of water are known to play an important role in concrete (Baroghel- 3) and/or salt (Eq. 4) (Olivella et al 1994).Constitutive laws are used to express these balance equations as a function of 124 the state variables liquid pressure, P l , gas pressure, P g , temperature, T and/or mass Thermo-hydraulic multiphase flow models of concrete 7 3.3 Thermo-hydraulic parameters 132The porosity and intrinsic permeability were taken from the experimental tests of 2). Results show that the latter never reach a saturation of 1. The most probable 154 reason is that the samples had suffered drying during preparation. Before measuring 155 the drying curve (i.e.,the retention curve from wet to dry) in the desiccators, the 156 sample had to be re-saturated. However, this may entrap air in the pores giving a 157 maximum saturation lower than 1. On the other hand, the evaporation test started 158 after concrete had hardened without any previous drying, so it is assumed that the 159 retention curve starts when the degree of saturation is 1. Geometry and mesh 161A one-dimensional domain of 20 cm length was assumed. and relative humidity were used, measured by the sensor situated above the columns 168 ( Figure 3). A summary of the parameters used in the boundary conditions is shown 169 in Table 2. For vapour flux at the top of the columns a mixed boundary condition 170 was applied (Eq. 5).Where super mixing between atmosphere and column. As it is difficult to assess a value to this 180 parameter, it has been calibrated. For the air flux, similarl...

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Section: Introductionmentioning

confidence: 99%

Characterization of Concrete by Calibrating Thermo-Hydraulic Multiphase Flow Models

2015

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“…10b (C = 1) with Fig. 10c (C = 6), that indicates the increase of C-S-H and C-A-H. Drying at 70 o C for w-d test evidently enhances the cementitious products (C-A-S-H) (Brue et al, 2012;Jiang & Yuan, 2013); i.e., an increased temperature results in a faster moisture diffusivity of the cementitious materials and hence cement hardening (Drouet et al, 2015;Wang, Fall, & Wu, 2016). The same is however not true for C > 6.…”

Section: Mineralogical and Microstructural Changesmentioning

confidence: 99%

“…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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“…Wu et al 2014;Rougelot et al 2009;Sémété et al 2016). Nevertheless, this approach does pose a problem of parasitic carbonation during the tests and calls for particular precaution: injection of inert gas for instance (Ranaivomanana et al 2011;Brue et al 2012;Q. Wu et al 2014).…”

Section: Introductionmentioning

confidence: 99%

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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Effect of temperature on the water retention properties of two high performance concretes

Cited by 79 publications

References 38 publications

Characterization of Concrete by Calibrating Thermo-Hydraulic Multiphase Flow Models

Characterization of Concrete by Calibrating Thermo-Hydraulic Multiphase Flow Models

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

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

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