Comparison of ASTM saturation techniques for measuring the permeable porosity of concrete

Safiuddin, Md.; Hearn, Nataliya

doi:10.1016/j.cemconres.2004.09.017

Cited by 143 publications

(64 citation statements)

References 5 publications

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“…The modification involved obtaining the saturated state of the specimen using vacuum-saturation method (following the procedure used for conditioning RCP specimens described in AASHTO T 277) rather than through boiling of specimens for 5 hours. The premise of the above modification was that the vacuum saturation provides higher saturation level than the boiling method for the specimens tested 24 hours after saturation is initiated (Safiuddin and Hearn 2005). However, in the present study the SSD mass and mass after immersion were checked periodically and were determined after no mass gain was observed.…”

Section: Test Proceduresmentioning

confidence: 99%

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

Radlinski¹,

Olek²

2010

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IntroductionConcrete bridge decks are inherently exposed to harsh environment. They are known to undergo degradation due to numerous distresses, of which the most common are corrosion of reinforcement (caused by ingress of chloride through bulk concrete), freeze-thaw damage, shrinkage cracking (aggravating both corrosion and freeze-thaw problems) and surface scaling due to deicing salts.Recently, high performance concrete (HPC) has become widely utilized in the applications where severe environment leads to premature deterioration. The premise behind the development of HPC was to address the durability issues typical of normal concrete. HPC almost always implies incorporation of mineral admixtures, such as fly ash (FA) or silica fume (SF). These materials are added to concrete for variety of reasons, of which the most important is improvement (compared to plain ordinary portland cement (OPC) concrete) of certain durabilityrelated properties. However, there are also some downsides of utilizing them in concrete. For example, fly ash is known to reduce the early age strength and early age resistance to chloride-ion penetration, as well as resistance to salt scaling and carbonation. Furthermore, fly ash concrete has been reported to be fairly sensitive to curing conditions compared to plain cement concrete. The shortcomings of incorporating silica fume, on the other hand, include increased susceptibility to shrinkage cracking and potentially reduced resistance to freezing and thawing.In the view of the aforementioned side effects associated with the use of fly ash or silica fume in binary mixtures, the ternary cementitious systems have been introduced as a potentially viable solution to address those durability issues. Superior properties of this kind of cementitious systems are commonly attributed to so-called synergistic effect taking place when both pozzolanic materials are utilized. The intuitively obvious benefit of the use of OPC/FA/SF mixtures is that the presence of fly ash in concrete compensates for the deficiencies of silica fume, and vice versa. For example, FA offsets the increase in water demand, heat of hydration and alkalinity of pore solution resulting from addition of SF. On the other hand, SF compensates for the low early age strength and sensitivity to curing (with respect to development of both mechanical and durability-related properties of FA concrete). From the economical perspective, a relatively low cost of FA counterbalances higher cost of SF. Although a fairly large amount of research has been conducted to evaluate the properties of ternary cementitious mixtures containing fly ash and silica fume, relatively little was done with the emphasis on the durability-related issues encountered when these binder systems are used in the bridge deck concrete. Up to date, no data exists on the actual performance of ternary concrete containing class C fly ash and silica fume in bridge decks.The purpose of this research was to examine the applicability of ternary binder systems containing ordinary port...

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Section: Test Proceduresmentioning

confidence: 99%

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

Radlinski¹,

Olek²

2010

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“…In this work the water saturated state is considered to be that obtained under vacuum (ASTM 1997), since this technique has been found to be the most efficient saturation procedure (Safiuddin and Hearn 2005). Nevertheless, the procedure can be applied considering other different saturation states (Nielsen and Geiker 2003).…”

Section: Methodsmentioning

confidence: 99%

“…Nevertheless, several authors have indicated that drying at 105ºC can produce irreversible microstructural modifications of the hardened cementitious matrices (Nokken and Hooton 2002;Safiuddin and Hearn 2005). This severe drying step can be avoided if the water absorption coefficient, A, is known.…”

Section: Obtaining the Drying Curves And The Water Absorption Coefficmentioning

confidence: 99%

An improved procedure for obtaining and maintaining well characterized partial water saturation states on concrete samples to be used for mass transport tests

et al. 2012

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A conditioning procedure is proposed allowing to install into the concrete specimens any selected value of water saturation degree with homogeneous moisture distribution. This is achieved within the least time and the minimum alteration of the concrete specimens. The protocol has the following steps: obtaining basic drying data at 50ºC (water absorption capacity and drying curves); unidirectional drying of the specimens at 50ºC until reaching the target saturation degree values; redistribution phase in closed containers at 50ºC (with measurement of the quasi-equilibrium relative humidities); storage into controlled environment chambers until and during mass transport tests, if necessary. A water transport model is used to derive transport parameters of the tested materials from the drying data, i.e. relative permeabilities and apparent water diffusion coefficients. The model also allows calculating moisture profiles during isothermal drying and redistribution phases, thus allowing optimization of the redistribution times for obtaining homogeneous moisture distributions.

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“… massa específica, segundo NBR13280/95 [16] com modificações;  porosidade aberta [17];  secagem;  absorção de água por capilaridade [18] e secagem;  isoterma de adsorção, segundo ASTM C 1498 [19];  ângulo de molhamento aparente.…”

Section: Programa Experimentalunclassified

Influência da cinza pesada empregada em substituição ao agregado natural nos mecanismos de transferência de umidade em argamassas

2007

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RESUMOO estudo da transferência de umidade é importante para a caracterização do comportamento das argamassas notoriamente no que se refere à durabilidade, à estanqueidade, à degradação de aspecto e ao desempenho térmico. No entanto, as pesquisas que abordam propriedades relacionados aos mecanismos de transferência de umidade apresentam resultados válidos apenas para argamassas convencionais. Em contrapartida, o uso de resíduos sólidos industriais e o emprego de aditivos têm sido cada vez mais intenso na construção civil. O objetivo do presente trabalho foi realizar a avaliação das propriedades relacionadas com os mecanismos de transferência de umidade não somente de argamassas convencionais, mas também de argamassas confeccionadas com teores de 50 e 100%, em volume, de cinzas pesadas em substituição ao agregado natural, contendo ou não aditivo incorporador de ar. A escolha da cinza pesada advém da grande disponibilidade deste resíduo na região sul do Brasil e da sua característica peculiar de apresentar conteúdo de umidade de equilíbrio bastante superior ao da areia. O estudo também abordou o aditivo incorporador de ar, pelo fato de atuar na formação de alvéolos não interligados ao longo dos capilares e promover a redução na massa específica aparente. As propriedades avaliadas foram: massa específica, porosidade aberta, cinética de absorção de água por capilaridade, cinética de secagem, adsorção e ângulo de molhamento aparente. Os resultados mostraram que o teor de cinza pesada e o emprego de aditivo incorporador de ar são parâmetros que afetam significativamente as propriedades relacionadas com a transferência de umidade. O programa experimental permitiu evidenciar que a natureza da cinza determina o nível da fixação de umidade da argamassa e a sua dinâmica na fixação.Palavras chaves: argamassas, cinzas pesadas, durabilidade, transferência de umidade, incorporador de ar. Influence of bottom ash replaced natural aggregate and air-entraining agent in moisture transfer mechanisms in mortars ABSTRACTThe study of moisture transfer has great importance for the characterization of mortars behavior, particularly in relation to durability, waterproofing, aesthetics degradation and the thermal performance. However, researches on properties related to moisture transfer mechanisms present applicable results only for conventional mortars. On the other hand, the use of industrial solid residues and admixtures are increasing in civil construction activities. The present work evaluated the properties related to moisture transfer mechanisms not only in conventional mortars, but also in mortars with 50% and 100% natural aggregate replaced by bottom ash, by volume, and with and without air-entraining agent. Bottom ash was chosen because it is a residue of great availability in southern Brazil, and its equilibrium moisture content is higher than that of sand, reflecting its porous nature. In relation to admixtures to cement-based materials, airentraining agent deserves prominence because it increases the disconnection of the capi...

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Comparison of ASTM saturation techniques for measuring the permeable porosity of concrete

Cited by 143 publications

References 5 publications

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

An improved procedure for obtaining and maintaining well characterized partial water saturation states on concrete samples to be used for mass transport tests

Influência da cinza pesada empregada em substituição ao agregado natural nos mecanismos de transferência de umidade em argamassas

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