Journal ArticleDOI
Measuring Permeability of Rigid Materials by a Beam‐Bending Method: I, Theory
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In this article, the authors extended this technique to other porous materials, such as porous glass and cement paste, and analyzed the force required to sustain the deflection as a function of time.Abstract:
When a saturated porous material is deformed, pressure gradients are created in the liquid, and the liquid flows within the pores to equilibrate the pressure. This phenomenon can be exploited to measure permeability : a rod of saturated porous material is instantaneously bent by a fixed amount, and the force required to sustain the deflection is measured as a function of time. The force decreases as the liquid flows through the pore network, and the rate of decrease depends on the permeability. This technique has been applied successfully to determine the permeability of gels, as well as their viscoelastic properties; in this paper the method is extended to ceramic materials, such as porous glass and cement paste. The theory has been modified to take account of the compressibility of the solid and liquid phases (whereas, those factors are negligible for gels). Analyses are presented for constant deflection, constant rate of deflection, and sinusoidal oscillation, where the solid phase is either purely elastic or viscoelastic, and the beam is either cylindrical or square. Experimental tests on Vycor® glass and cement paste will be presented in companion papers.read more
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Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment
TL;DR: In this article, a new analysis tool was developed to quantify the experimentally observed changes in morphology of portlandite, allowing the calculation of the relative surface energies of the crystal facets.
Book
Water Transport in Brick, Stone and Concrete
Christopher Hall,William D. Hoff +1 more
TL;DR: Porous Materials Water in Porous Materials Flow in porous materials Unsaturated Flows UnSaturated Flow in Building Physics Composite Materials Evaporation and Drying Topics in Water Transport Appendices Symbols Used Properties of Water Minerals, Salts and Solutions Other Liquids Other Data as mentioned in this paper
Journal ArticleDOI
A review of salt scaling: II. Mechanisms
TL;DR: In this article, a review of the state of the art in this field is presented, and proposed mechanisms are discussed, and their adequacy is judged based on their ability to account for the phenomenology.
Journal ArticleDOI
Coefficient of thermal expansion of cement paste and concrete: Mechanisms of moisture interaction
TL;DR: In this paper, the authors demonstrate the strong effect of moisture content on CTE, and discuss the mechanism(s) based on experimental results on mature cement paste, and use the temperature variation of the relative humidity exerted by the pore water to explain the high CTE of partly dried specimens.
Journal ArticleDOI
Quantifying the effects of crack width, tortuosity, and roughness on water permeability of cracked mortars
TL;DR: In this paper, the authors quantify the water permeability of localized cracks as a function of crack geometry (i.e., width, tortuosity, and surface roughness).
References
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Journal ArticleDOI
Theory of Propagation of Elastic Waves in a Fluid‐Saturated Porous Solid. I. Low‐Frequency Range
TL;DR: In this article, a theory for the propagation of stress waves in a porous elastic solid containing compressible viscous fluid is developed for the lower frequency range where the assumption of Poiseuille flow is valid.
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Auxetic foams: Modelling negative Poisson's ratios
TL;DR: In this article, a reentrant cell shape is defined that has the unusual property of exhibiting a negative Poisson's ratio, and a finite element model for three-dimensional, open-called foams is developed.
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Bending of gel beams: method for characterizing elastic properties and permeability
TL;DR: In this paper, the kinetics of deformation of a rod are analyzed, showing that it is possible to obtain the permeability, D, of the gel from the time-dependence of the load, as well as finding both G p and E p.
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Elastodynamics of gels
TL;DR: In this article, a unified description of the normal modes in a gel is presented; parameters deduced from measurement on a given mode are shown to influence the properties of the others.
Journal ArticleDOI
Volume Relaxation Far from Equilibrium
TL;DR: In this article, the authors applied Narayanaswamy's model of structural relaxation to the data of Hara and Suetoshi on volume relaxation in plate glass and used both the Adam-Gibbs and Arrhenius equations to represent the relaxation time.