A new technique for measuring the air permeability of near-surface concrete

Dhir, Ravindra K.; Hewlett, P. C.; Byars, E A; Shaaban, Ibrahim G.

doi:10.1680/macr.1995.47.171.167

Cited by 24 publications

(21 citation statements)

References 6 publications

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“…Using CEM I grouts, Dewaele et al [9] obtained permeability decrease of several orders of magnitude after carbonation (by injection under pressure of CO 2 -rich water). Claisse et al [6] carbonated CEM I concretes (5% CO 2 ) and measured significant increase in the so-called impermeability index [18] indicating a fall in permeability. In the same way Song and Kwon [19] carbonated two CEM I concretes and found that the permeability coefficient of the carbonated concretes was three times less than that of the non-carbonated ones.…”

Section: Introductionmentioning

confidence: 99%

Impact of carbonation on unsaturated water transport properties of cement-based materials

Auroy

Poyet

Bescop

et al. 2015

Cement and Concrete Research

129

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International audienceIn unsaturated conditions, the durability of concrete structures is strongly dependent on the evolution of the amount of free water within concrete porosity. Reliable durability assessment of concrete structures in relation to their environment thus requires accurate unsaturated water transport description as well as reliable input data. The effect of carbonation on water transport remains poorly studied and data are lacking. It was then the purpose of this article to acquire all the data needed to describe unsaturated water transport in carbonated cementitious materials (porosity, water retention and unsaturated permeability). Four hardened pastes made with four different binders were carbonated at 3% CO2 to ensure representativeness with natural carbonation. Beyond the modification of the water retention curve and porosity clogging, significant microcracking due to carbonation shrinkage was observed. The consequence on permeability highlighted a competition between porosity clogging and microcracking that was dependent on the initial mineralogical composition

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Section: Introductionmentioning

confidence: 99%

Impact of carbonation on unsaturated water transport properties of cement-based materials

Auroy

Poyet

Bescop

et al. 2015

Cement and Concrete Research

129

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“…MC refers to the moisture cured concrete, under which condition additional moisture was present in the concrete and no significant drying occurred from the surface in the whole curing period. The moisture content in the surface region was sufficient to yield low permeability (12,14). With respect to SC, concrete was sealed after 3 day water curing.…”

Section: Determination Of Steady-state Flow Rate Under Two Pressure Hmentioning

confidence: 99%

“…The second approach is to remove moisture from the sample by certain pre-conditioning methods. Dhir et al (12) suggested that vacuum dewatering could be used to eliminate the influence of moisture on results. Schonlin and Hilsdorf (13) used a hot air gun to dry out the moisture around test area prior to measurements.…”

Section: Introductionmentioning

confidence: 99%

Use of Two-Pressure-Head Method to Assess Water Permeability of Structural Concrete

Yang¹,

Chen²,

Long³

et al. 2018

ACI Materials Journal

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Determining the water permeability of concrete in structures remains a conundrum because of difficulties in removing the influences of moisture. This study describes the extended flow-net theory developed on the basis of the two pressure head concept, which provides a means of measuring permeability under the partially saturated condition. Surface mounted tests and the standard laboratory water penetration tests were carried out to verify this approach. Before determining the water permeability, steady state flow rates at two different pressure levels were evaluated and the effects of initial moisture conditions on flow behaviour were investigated. The results indicate that the proposed approach does offer a useful means of determining the water permeability of structural concrete, although it cannot be claimed to be universally applicable for all moisture conditions likely to be encountered in practice.

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“…Besides, a high water pressure must be applied to obtain measurable flows, which can damage the studied medium. Insitu tests have also been developed (Claisse et al, 2003;Figg 1973;Basheer et al, 1994;Dhir et al, 1995). A number of laboratory based tests have been developed to measure the gas permeability of concrete and mortars, including the Cembureau test (Verdier and Carcassès, 2002;Kollek, 1989;Abbas et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Permeability and porosity improvement of grouted sand

Saiyouri¹,

Alaïwa²,

Hicher³

2011

European Journal of Environmental and Civil Engineering

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Over the past twenty years, grouting technology allowed to treat a wide range of subsurface conditions for construction. When a properly designed cement grout is injected into sand soil, homogeneous grout bulbs are formed which make dense and thus strengthen the surrounding soil. For successful grouting, the knowledge of subsurface conditions is important. Ground improvement can be assessed by permeability testing and mercury porosimetry testing. Laboratory experiments were conducted to examine grout injection through Loire sand columns under saturated conditions. These tests were performed in order to highlight the effect of some key factors: cement-to-water ratio, relative density of the granular skeleton on the properties of the grouted sand. Subsequently Mercury Intrusion Porosimetry tests showed that both porosity and its distribution are modified. Besides, the intrinsic permeability was measured by a gas permeability device. Then, an evaluation of intrinsic permeability using the Katz-Thompson equation on these tests is proposed and compared to gas permeability which is still commonly used in civil engineering to measure this intrinsic parameter.RÉSUMÉ. Pendant les vingt dernières années, la technologie de l'injection des sols a permis de traiter un grand nombre de terrains pour une bonne préparation à la construction. Quand un coulis de ciment correctement conçu est injecté dans un sable, des bulbes d'injection sont formés ce qui densifie et renforce ainsi le sol environnant. Pour réussir l'opération d'injection, la connaissance des conditions du sous-sol est importante. L'amélioration des sols injectés peut être évaluée par des tests de perméabilité et de porosimétrie par intrusion de mercure. Des expériences de laboratoire ont été conduites pour examiner l'injection de coulis dans des colonnes de sable de Loire dans des conditions saturées. Ces essais ont été exécutés pour mettre en évidence l'effet de quelques facteurs clefs : proportion de ciment-eau, densité relative du squelette granulaire sur les propriétés du sable injecté. Par la suite, les essais de porosimétrie mercure ont montré que tant la porosité que sa distribution sont modifiées. En plus, la perméabilité intrinsèque a été mesurée par un dispositif de perméabilité au gaz. On propose ensuite une évaluation de la perméabilité intrinsèque utilisant l'équation Katz-Thompson sur ces essais qui est comparée à la perméabilité au gaz qui est généralement utilisée en génie civil pour mesurer ce paramètre intrinsèque.

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A new technique for measuring the air permeability of near-surface concrete

Cited by 24 publications

References 6 publications

Impact of carbonation on unsaturated water transport properties of cement-based materials

Impact of carbonation on unsaturated water transport properties of cement-based materials

Use of Two-Pressure-Head Method to Assess Water Permeability of Structural Concrete

Permeability and porosity improvement of grouted sand

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