Oven-drying as a preconditioning method for air permeability test on concrete

Sanjuán, Miguel Ángel; Muñoz-Martialay, R.

doi:10.1016/0167-577x(95)00283-9

Cited by 17 publications

(8 citation statements)

References 9 publications

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“…This variation is relatively small and illustrates the good reproducibility of the material on one hand. On the other hand, these values are overestimated, compared to usual concrete which is never completely dry, because of moisture and drying shrinkage cracking effects [10,15,16]. Nevertheless, all the specimens considered here possess the same initial microstructural state.…”

Section: Resultsmentioning

confidence: 89%

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Effects and interactions of temperature and stress-level related damage on permeability of concrete

Choińska

Khelidj

Chatzigeorgiou

et al. 2007

Cement and Concrete Research

217

108

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International audienceThe objective of this study is to investigate damage-temperature-stress level-permeability interactions in structural concrete. The tests are performed on hollow cylindrical concrete specimens, subjected to compressive loading and temperature up to 150 °C. The results emphasize that at stress levels lower than 80% of the peak stress, the variation of permeability is small and it is slightly influenced by the stress. As a matter of fact, the permeability under load is smaller than the permeability measured after unloading. As the load exceeds 80% of the peak stress, micro-cracking increases rapidly, causing an increase of the permeability and a greater sensitivity to the applied load, i.e. a noticeable difference between the permeability measured under load and after unloading, the first becoming greater than the latter. In the post-peak phase the increase of permeability is much larger due to significant crack width growth. The increase of permeability with the applied load seems to be greater with temperature, inducing further alterations of concrete and dilation of the porous structure of the material. Finally, the experimental results seem to agree with the format of coupled evolution of the permeability due to damage and temperature assumed by Gawin et al. [D. Gawin, C.E. Majorana, B.A. Schrefler, Numerical analysis of hygro-thermal behaviour and damage of concrete at high temperature, Mechanics of Cohesive-Frictional Materials 4 (1999) 37–74.]

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Section: Resultsmentioning

confidence: 89%

“…The gas permeability is strongly influenced by the moisture content in the material, as shown in Refs. [15,16]. The chemical dehydration of the cement paste modifies geometry of the microstructure; concrete hydraulic behaviour is thus affected [17].…”

Section: Introductionmentioning

confidence: 99%

Effects and interactions of temperature and stress-level related damage on permeability of concrete

Choińska

Khelidj

Chatzigeorgiou

et al. 2007

Cement and Concrete Research

217

108

View full text Add to dashboard Cite

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“…Some authors have found that the microstructure of cementitious materials may be damaged at a temperature above 60 °C because of the deterioration of ettringite or CSH (25,26). However, others found that the effect of temperature on the microstructure is low when the temperature is below 105 °C (27).…”

Section: Porosity Density and Apparent Permeabilitymentioning

confidence: 99%

Composite cement mortars based on marine sediments and oyster shell powder

Ez-zaki¹,

Diouri²,

Kamali-Bernard³

et al. 2016

Mater. construcc.

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Additions of dredged marine sediments and oyster shell powder (OS) as cement substitute materials in mortars are examined by several techniques. The sediments have high water and chloride contents and calcite, quartz, illite and kaolinite as principal minerals. The OS powders are entirely composed of calcium carbonate and traces of other impurities. Four mixtures of treated sediments and OS powders at 650 °C and 850 °C are added to Portland cement at 8%, 16% and 33% by weight. The hydration of composite pastes is followed by calorimetric tests, the porosity accessible to water, the bulk density, the permeability to gas, the compressive strength and the accelerated carbonation resistance are measured. In general, the increase of addition amounts reduced the performance of mortars. However, a reduction of gas permeability was observed when the addition was up to 33%. Around 16% of addition, the compressive strength and carbonation resistance were improved. RESUMEN: Morteros de cemento basado en sedimentos marinos y polvo de concha de ostra.En este trabajo se ha valorado la sustitución de cemento en morteros por sedimentos marinos dragados y polvo de concha de ostra (OS). Los sedimentos tienen altos contenidos de agua, cloruros, calcita, cuarzo, illita y caolinita como minerales principales. Los polvos OS están compuestos de carbonato cálcico y trazas de otras impurezas. Se añadieron a un cemento Portland, cuatro mezclas de los sedimentos y polvos de OS tratados a 650 °C y 850 °C en proporciones del 8%, 16% y 33% en peso. La hidratación de pastas se estudió a través de calorimetría. Se estudió además la porosidad accesible al agua, densidad aparente, permeabilidad al gas, resistencia a compresión y carbonatación acelerada. En general, un aumento en la adición produjo una reducción del rendimiento de los morteros. Se observó, sin embargo, una reducción de la permeabilidad a los gases con porcentajes de adición de hasta el 33%. Con valores del 16% de sustitución, mejoraron las resistencias mecánicas y la resistencia frente a la carbonatación.

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“…The permeability of low-permeability materials is investigated in several laboratories using different liquid or gas methods [7][8][9][10][11][12][13]. The tests are carried out on samples previously cored from the on site test zone.…”

Section: Introductionmentioning

confidence: 99%