Capillary absorption of water and n-decane by autoclaved aerated concrete

Ioannou, Ioannis; Hamilton, Alister; Hall, Christopher

doi:10.1016/j.cemconres.2008.01.013

Cited by 60 publications

(29 citation statements)

References 12 publications

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“…Porous structure of AAC can absorb up to 100% of water and even more [37]. This phenomenon has been explained by Ioannu et al [38] as a result of structural aspects of partitions between pores.…”

Section: Extensive Substratementioning

confidence: 86%

Effect of P-Reactive Drainage Aggregates on Green Roof Runoff Quality

Karczmarczyk

Baryła

Bus

2014

Water

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Abstract:The main hypothesis of the presented study is that the negative effect of phosphorus leaching from a green roof substrate can be reduced by including P-reactive material in a drainage layer. In this work, different aggregates (Pollytag ® , lightweight expanded clay aggregates, chalcedony, serpentynite and crushed autoclaved aerated concrete) to be used as the green roof drainage layer are described. Physical parameters, e.g., granulometric composition, water absorption, bulk density and porosity are assessed. A phosphorus sorption isotherm and a kinetic test were performed. Physical and chemical characteristics of the materials were used as a base for choosing the best media for the drainage layer. The P-removal efficiency of crushed autoclaved aerated concrete was confirmed in a column experiment. Adding the implementation of the P-reactive material in a drainage layer during construction can reduce the negative effect of substrate on green roof runoff quality.

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Section: Extensive Substratementioning

confidence: 86%

Effect of P-Reactive Drainage Aggregates on Green Roof Runoff Quality

Karczmarczyk

Baryła

Bus

2014

Water

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“…We used the basic formula for calculating κ app given in [9] and obtained the following results with the sorptivities measured by other investigators: Ytong-CZ [3] (bulk density of 450 kg · m −3 )-κ app ≈ 5.0 × 10 −8 m 2 · s −1 , Ytong-CZ [20] (400 kg · m −3 )-κ app ≈ 6.1 × 10 −8 m 2 · s −1 , Ytong-DK [23] (450 kg · m −3 )-κ app ≈ 3.0 × 10 −9 m 2 · s −1 . While the values of κ app for AAC investigated in [3] and [20] were up to 50 % higher than the highest values of the moisture diffusivity of AAC analyzed in this article, for AAC studied in [23], κ app was almost a factor of two less than our lowest κ values. In [26], the author determined κ(u) of AAC with a bulk density of 500 kg · m −3 in a series of absorption tests and obtained κ ≈ 2 × 10 −8 m 2 · s −1 for lowest moisture contents and κ ≈ 1 × 10 −6 m 2 · s −1 for highest moisture contents, i.e., values approximately one order of magnitude higher than in this article.…”

Section: Resultsmentioning

confidence: 95%

“…A possible explanation is in the effect of gravity. The SEM analysis in [23] revealed for a similar AAC of the same manufacturer an unusual micro/macro-structure, which comprises a fine pored matrix within which are dispersed large aeration pores formed by foaming the wet slurry. While the fine pores of the matrix make good prerequisites for fast capillary transport, the aeration pores have weak capillary suction.…”

Section: Resultsmentioning

confidence: 98%

“…Therefore, a direct comparison of results obtained in this article with data published by other investigators was difficult. The authors of previous studies were mostly focused on the determination of water sorptivity [3,20,23]. However, using water sorptivity values, only the apparent moisture diffusivity κ app can be estimated, as already mentioned in Sect.…”

Section: Resultsmentioning

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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“…More recently, marked deviations from linearity between i and t 1/2 have been observed in autoclaved aerated concrete [21] and vuggy limestone [22] where there is a bimodal pore size distribution comprised of fine matrix pores and large coarse pores. In these studies, the authors attributed this abnormal imbibition behaviour to the presence of large pores which contribute substantially to the total porosity but provide little capillary action and do not conform to the standard t 1/2 sorptivity.…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

Song¹,

Mitchell²,

Jaffel³

et al. 2011

J. Phys. D: Appl. Phys.

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In this paper we investigate both capillary water imbibition and the sorptivity of aerated gypsum plaster, and how these sorption characteristics are related to the pore structure of the material. These characteristics are examined by monitoring mass change using the conventional gravimetric method and by obtaining water content profiles using non-destructive magnetic resonance imaging (MRI) techniques during capillary imbibition of water. Here, three different gypsum samples are investigated: one non-aerated reference gypsum sample and two aerated gypsum samples produced with different volumetric air fractions. The capillary water absorption into the reference sample follows t 1/2 kinetics (Fickian diffusion), where t is the time of ingress. However, in the aerated gypsum samples there are deviations from t 1/2 kinetics. The MRI results show unambiguously that two wetting fronts advance through the aerated structure; an observation that cannot be made from the gravimetric data alone. The water content profiles of the aerated gypsum samples are therefore analysed by treating them as the sum of two separate absorption processes using sharp front analysis. The capillary water absorption properties of this material are well described as a parallel combination of fast absorption into fine matrix pores and slow absorption into a modified structure of matrix pores inter-connected to air voids introduced into the slurry by aeration.

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Capillary absorption of water and n-decane by autoclaved aerated concrete

Cited by 60 publications

References 12 publications

Effect of P-Reactive Drainage Aggregates on Green Roof Runoff Quality

Effect of P-Reactive Drainage Aggregates on Green Roof Runoff Quality

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

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

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