Flue gas desulfurization gypsum: Study of basic mechanical, hydric and thermal properties

Tesárek, Pavel; Drchalová, J.; Kolı́sko, Jiřı́; Rovnanı́ková, Pavla; Černý, Robert

doi:10.1016/j.conbuildmat.2006.05.009

Cited by 116 publications

(57 citation statements)

References 10 publications

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“…Differences as large as one order of magnitude were observed when comparing the moisture diffusivity values at low and high moisture contents. Similar results were reported for other materials [10,11]. The results also show the importance of the temperature in moisture transport.…”

Section: Resultssupporting

confidence: 92%

“…The sorptivity S can be used to estimate the moisture diffusivity [8] but if S is the only parameter known (besides the saturation moisture content), the accuracy is usually insufficient. An assumption of a constant moisture diffusivity which is often adopted [9] is clearly too strong; the moisture diffusivity can vary with moisture content over a range of several orders of magnitude [10,11]. Approximate formulas devised to express a dependence of the moisture diffusivity on the moisture content on the basis of a known S value [12] include empirical parameters which have questionable accuracy if generalized; they are usually derived for specific types of porous materials.…”

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confidence: 99%

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Determination of Moisture Diffusivity as a Function of Both Moisture and Temperature

Pavlík

Černý

2011

Int J Thermophys

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The effect of moisture and temperature on liquid water transport in porous media was studied. Specimens of autoclaved aerated concrete were subjected to one-sided water penetration in isothermal conditions at temperatures of 20 • C, 40 • C, 60 • C, and 80 • C. After specified time intervals, moisture profiles were determined gravimetrically. The moisture diffusivity was calculated for a particular temperature as a function of moisture content, using an inverse analysis. The results demonstrate the dependence of the moisture diffusivity on the moisture content and the temperature of the samples. The moisture diffusivity for high moisture content can be as much as one order of magnitude greater than for the lowest moisture content studied. The moisture diffusivity was found to increase by as much as a factor of two when the temperature is increased from 20 • C to 80 • C.

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Section: Resultssupporting

confidence: 92%

mentioning

confidence: 99%

Determination of Moisture Diffusivity as a Function of Both Moisture and Temperature

Pavlík

Černý

2011

Int J Thermophys

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“…Typical reactions are the reaction of the aluminium sulphate with the calcium carbonate (1) or the decomposition of the ammonium bicarbonate in the water (2). The preparation of the lightweight gypsum foamed by gas released from this reaction can be seen at Fig.…”

Section: Chemical Lightening By Gasmentioning

confidence: 99%

“…Gypsum can be also made from large scale of waste products, originating e.g. in the fertilizers production (phosphogypsum) [1] or in the coal power plants from flue gas desulfurization (FGD gypsum) [2].…”

Section: Introductionmentioning

confidence: 99%

Lightweight Gypsum Based Materials: Methods of Preparation and Utilization

Doleželová¹,

Krejsová²,

Vimmrová³

2017

Int. J. SDP

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Although gypsum is one of the most environmentally friendly building binders, its use in the buildings is relatively limited and therefore the broadening of the gypsum product portfolio is desirable. One possibility is the development of the lightweight gypsum materials with better thermal insulation properties, attractive acoustic properties and also lower transportation costs. The lightweight gypsum materials can be used in a similar way as an aerated autoclaved concrete (AAC), whose energy consumption at production is several times higher.The main methods of the preparation of gypsum-based lightweight materials are described and compared. Gypsum can be lightened indirectly by the lightweight filler or directly. In the directly lightened materials, the pores are introduced into the gypsum material either by some chemical reaction producing gas or by the help of surface active substances. For the chemical lightening a large scale of waste products can be used. Lightening by the help of waste stone powder is described in detail. The materials with the properties comparable with the properties of AAC were prepared. Their bulk density was under 600 kg/m 3 , compressive strength was about 2 MPa and coefficient of thermal conductivity was under 0.2 W/m.K.Lightweight gypsum materials can be used as a thermal insulating blocks, for the lightweight gypsum boards, partitions blocks, lightweight fire-resistant plasters or thermal-insulating plasters.

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“…The composition of gypsum materials is shown in Table 1. The material properties of non-modified and modified gypsum were measured in the Laboratory of Transport Processes (LTP), Faculty of Civil Engineering, Czech Technical University in Prague [4]. They are given in Table 2, where ρ is the bulk density, c the specific heat capacity, κ the moisture diffusivity, µ the water vapor diffusion resistance factor, θ sat the saturated moisture content, θ hyg the maximum hygroscopic moisture content, λ the thermal conductivity.…”

Section: Materials and Building Envelopesmentioning

confidence: 99%

Coupled heat and moisture transport in a building envelope on cast gypsum basis

Mad¹,

'²,

Tesárek³

et al. 2006

WIT Transactions on Engineering Sciences, Vol 53

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Flue gas desulphurization (FGD) gypsum can be potentially used as a material for load bearing structures. In this paper, a computational assessment of hygrothermal performance of a building envelope based on several modifications of FGD gypsum is presented. In the computer simulations of temperature and relative humidity fields, three variations of FGD gypsum wall, based on the raw material and on two types of hydrophobized gypsum, with the thickness of 300 mm, are solved. The thermal insulation function of the wall is achieved by exterior thermal insulation boards with the thickness of 100 mm, which are considered in four variants. Insulation I is hydrophilic material with a low value of hygroscopic moisture content on mineral wool basis, Insulation II capillary active material with higher value of hygroscopic moisture content on calciumsilicate basis, Insulation III hydrophobic material with a low value of water vapor resistance factor on mineral wool basis and Insulation IV hydrophobic material with higher value of water vapor resistance factor on polystyrene basis. Lime plaster with the thickness of 10 mm is used on the exterior wall surface. The computational analysis reveals that use of hydrophobization admixtures in the gypsum element does not lead to any improvement of hygrothermal behavior of the envelope provided by an exterior thermal insulation. Therefore, the application of a gypsum element without any hydrophobization seems to be a more favorable solution. The common hydrophobized thermal insulation materials on the basis of polystyrene or mineral wool are found to be satisfactory from the point of view of hygrothermal performance of the analyzed castgypsum based envelope.

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Flue gas desulfurization gypsum: Study of basic mechanical, hydric and thermal properties

Cited by 116 publications

References 10 publications

Determination of Moisture Diffusivity as a Function of Both Moisture and Temperature

Determination of Moisture Diffusivity as a Function of Both Moisture and Temperature

Lightweight Gypsum Based Materials: Methods of Preparation and Utilization

Coupled heat and moisture transport in a building envelope on cast gypsum basis

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