Water movement in porous building materials—II. Hydraulic suction and sorptivity of brick and other masonry materials

Gummerson, R. J.; Hall, Christopher; Hoff, W D

doi:10.1016/0360-1323(80)90015-3

Cited by 145 publications

(83 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Transport properties can either be characterized by means of a water absorption coefficient estimated by weighing samples during free water uptake experiments [21,22], or by monitoring concentration profiles in the samples. The latter approach allows characterizing the entire profile of unsaturated moisture permeability.…”

Section: Hygric Characterizationmentioning

confidence: 99%

Characterization of fracture patterns and hygric properties for moisture flow modelling in cracked concrete

Rouchier

Janssen

Rode

et al. 2012

Construction and Building Materials

View full text Add to dashboard Cite

International audienceSeveral years after their installation, building materials such as concrete present signs of ageing in the form of fractures covering a wide range of sizes, from microscopic to macroscopic cracks. All sizes of fractures can have a strong influence on heat and moisture flow in the building envelope, but their distribution is difficult to predict due to the variety of environmental factors which cause them. This paper aims at applying experimental non-destructive techniques for the observation of fracture patterns and of fluid flow in fractures, in order to provide this data to models for fluid transfer in fractured porous media. Digital image correlation was performed during the fracturing of concrete samples, in which moisture uptake was then monitored using X-ray radiography. Finite-element simulations were then performed based on the measurements of the fracture patterns, in order to recreate the measured moisture concentration profiles. Digital image correlation was found suitable as a mean to obtain a complete mapping of the deformations at the surface of the samples, and a first step was made towards the use of non-destructive fracture characterization for the purpose of moisture transfer modelling

show abstract

Section: Hygric Characterizationmentioning

confidence: 99%

Characterization of fracture patterns and hygric properties for moisture flow modelling in cracked concrete

Rouchier

Janssen

Rode

et al. 2012

Construction and Building Materials

View full text Add to dashboard Cite

show abstract

“…In recent years, the concept of sorptivity, developed originally from unsaturated flow theory for water transport in soil physics [6][7][8], has been applied successfully to describe capillary water absorption processes in many porous building materials [9][10][11][12][13][14][15]. The total volume of liquid absorbed by a porous building material during one-dimensional capillary absorption is given by (1) where i(t) is the cumulative volume of liquid absorbed at time t per unit area of surface.…”

Section: Introductionmentioning

confidence: 99%

“…A more recent review by Hall [20] gives the theoretical background and practical aspects of assessing the sorptivity of building materials in the laboratory. Since the interpretation of experimental data requires some understanding of the theoretical basis of unsaturated flow, a brief explanation of the theory of sorptivity is given in section 2 [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…However, measuring 'bound' water is not required to study the macroscopic hydraulic properties of porous building materials. Over the past decades, MRI techniques have proven to be extremely reliable for visualising the water distribution and quantifying the dynamic transport of water in porous building materials [9,10,15,[39][40][41][42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

“…By combining (4) with the requirement of continuity, the water movement in a partially saturated material is described by the following diffusion equation [6][7][8][9][10] …”

Section: Unsaturated Flow Theorymentioning

confidence: 99%

See 2 more Smart Citations

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

Song¹,

Mitchell²,

Jaffel³

et al. 2011

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

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.

show abstract

Salt weathering: influence of evaporation rate, supersaturation and crystallization pattern

Rodríguez-Navarro

Doehne

1999

Earth Surf. Process. Landforms

535

340

View full text Add to dashboard Cite

Micro-and macroscale experiments which document the dynamics of salt damage to porous stone have yielded data which expose weaknesses in earlier interpretations. Previously unexplained differences are found in crystal morphology, crystallization patterns, kinetics and substrate damage when comparing the growth of mirabilite (Na 2 SO 4 . 10H 2 O) and thenardite (Na 2 SO 4 ) versus halite (NaCl). The crystallization pattern of sodium sulphate was strongly affected by relative humidity (RH), while a lesser RH effect was observed for sodium chloride. Macroscale experiments confirmed that mirabilite (crystallizing at RH>50 per cent) and thenardite (crystallizing at RH<50 per cent) tend to form subflorescence in highly localized areas under conditions of constant RH and temperature. This crystallization pattern was more damaging than that of halite, since halite tended to grow as efflorescence or by filling the smallest pores of the stone in a homogeneous fashion, a result which contradicts Wellman and Wilson's theoretical model of salt damage. Low RH promoted rapid evaporation of saline solutions and higher supersaturation levels, resulting in the greatest damage to the stone in the case of both sodium sulphate and sodium chloride crystallization. At any particular crystallization condition, sodium chloride tended to reach lower supersaturation levels (resulting in the crystallization of isometric crystals) and created negligible damage, while sodium sulphate reached higher supersaturation ratios (resulting in non-equilibrium crystal shapes), resulting in significant damage. ESEM showed no damage from sodium sulphate due to hydration. Instead, after water condensation on thenardite crystals, rapid dissolution followed by precipitation of mirabilite took place, resulting in stone damage by means of crystallization pressure generation.It is concluded that salt damage due to crystallization pressure appears to be largely a function of solution supersaturation ratio and location of crystallization. These key factors are related to solution properties and evaporation rates, which are constrained by solution composition, environmental conditions, substrate properties, and salt crystallization growth patterns.When combined with a critical review of salt damage literature, these experiments allow the development of a model which explains variations in damage related to combinations of different salts, substrates and environmental conditions.

show abstract

Water movement in porous building materials—II. Hydraulic suction and sorptivity of brick and other masonry materials

Cited by 145 publications

References 8 publications

Characterization of fracture patterns and hygric properties for moisture flow modelling in cracked concrete

Characterization of fracture patterns and hygric properties for moisture flow modelling in cracked concrete

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

Salt weathering: influence of evaporation rate, supersaturation and crystallization pattern

Contact Info

Product

Resources

About