Fracture energy and fracture process zone

Hu, Xiao; Wittmann, Folker H.

doi:10.1007/bf02472590

Cited by 235 publications

(80 citation statements)

References 13 publications

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“…The values determined by the work-of-fracture method as proposed in RILEM recommendation (RILEM 1985) are dependent on the specimen size and shape used in the test, as demonstrated and analyzed by several researchers in the past (Hu and Wittmann 1992;Kwon et al 2008;Muralidhara et al 2011;RILEM 2004;Vydra et al 2012). The two most popular models to obtain a size-independent specific fracture energy of concrete (also called true fracture energy are the boundary effect model of Hu and Wittmann (1992) and the experimental correction model to avoid energy dissipations proposed by Guinea et al Guinea et al 1992;Planas et al 1992).…”

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

“…The two most popular models to obtain a size-independent specific fracture energy of concrete (also called true fracture energy are the boundary effect model of Hu and Wittmann (1992) and the experimental correction model to avoid energy dissipations proposed by Guinea et al Guinea et al 1992;Planas et al 1992). Although these models are based on different fundamentals, they are related to each other.…”

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

“…Although these models are based on different fundamentals, they are related to each other. Cifuentes et al (2013) showed that if the size-dependent G f measured by the RILEM method is corrected according to the method of Elices and co-workers Guinea et al 1992;Planas et al 1992) or that of Hu and Wittmann (1992) (the latter admits a simplification as proposed by Karihaloo et al (2003) if the notch to depth ratios are well apart from each other), then the resulting specific fracture energy G F is very nearly the same and independent of the size of the specimen.…”

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

“…The methodology of Hu and Wittmann (1992), based on the local fracture energy concept as thoroughly detailed in several papers (Cifuentes and Karihaloo 2013;Hu and Wittmann 1992), states that the size effect on G f (measured specific fracture energy according to work-of-fracture method) is caused by a variation of the fracture process zone when the crack approaches the free boundary surface of the specimen at test completion (Hu and Wittmann 1992). On the other hand, among the several sources of experimental errors analyzed by Guinea et al, the most significant proves to be the influence of the non-measured fracture energy of concrete due to the curtailment of the upper tail of the P-d curve .…”

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

“…In that way, six different sizes of the ligament area are tested for each concrete mix and the influence of the specimen geometry can be analyzed. As stated by different researchers, the size effect on fracture energy can be accurately analyzed by varying the relative notch depth (Cifuentes and Karihaloo 2013;Hu and Wittmann 1992). In this case, even if the outside diameter of specimen remains the same, a variation in the position of the axis of the steel pulling bars allows the effective height (size) of the specimens to be varied.…”

Section: Modified Disk-shaped Compact Tension Testsmentioning

confidence: 99%

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Modified Disk-Shaped Compact Tension Test for Measuring Concrete Fracture Properties

Cifuentes

Lozano

Holušová

et al. 2017

Int J Concr Struct Mater

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A new approach for measuring the specific fracture energy of concrete denoted modified disk-shaped compact tension (MDCT) test is presented. The procedure is based on previous ideas regarding the use of compact tension specimens for studying the fracture behavior of concrete but implies significant modifications of the specimen morphology in order to avoid premature failures (such as the breakage of concrete around the pulling load holes). The manufacturing and test performance is improved and simplified, enhancing the reliability of the material characterization. MDCT specimens are particularly suitable when fracture properties of already casted concrete structures are required. To evaluate the applicability of the MDCT test to estimate the size-independent specific fracture energy of concrete (G F ), the interaction between the fracture process zone of concrete and the boundary of the MDCTspecimens at the end of the test is properly analyzed. Further, the experimental results of G F obtained by MDCT tests for normal-and high-strength selfcompacting concrete mixes are compared with those obtained using the well-established three-point bending test. The procedure proposed furnishes promising results, and the G F values obtained are reliable enough for the specimen size range studied in this work.

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Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

Section: Size Dependency Of the Specific Fracture Energy Of Concretementioning

confidence: 99%

Section: Modified Disk-shaped Compact Tension Testsmentioning

confidence: 99%

See 3 more Smart Citations

Modified Disk-Shaped Compact Tension Test for Measuring Concrete Fracture Properties

Cifuentes

Lozano

Holušová

et al. 2017

Int J Concr Struct Mater

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Effect of meso‐structure on strength and size effect in concrete under tension

Murali

Deb

2017

Num Anal Meth Geomechanics

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SummaryThe effect of heterogeneity in meso level geometric and material properties on tensile strength and size effect in split cylinder specimens is investigated. Critical meso geometric parameters are identified by studying their influence on the evolution of the fracture process zone. A statistical analysis is used to account for dependencies between the parameters. A reversal of the size effect, important for the strength of field specimens, is observed for certain meso geometries. Meso level explanations for this are proposed, and meso geometries likely to show such a reversal are identified. For moderately sized specimens, major trends in the size effect are seen to be almost entirely explained by heterogeneity in the meso geometry. KEYWORDS concrete, discrete element method, meso-structure, size effect

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Size effect on fracture energy induced by non‐locality

Jirásek

Rolshoven

Grassl

2004

Num Anal Meth Geomechanics

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SUMMARYExperimental results available in the literature indicate that the nominal fracture energy of concrete (defined as total work of fracture divided by the ligament area) depends on the size of the specimen. Theoretical modelling of the size effect on nominal fracture energy based on a non-local constitutive model is attempted in this paper. The influence of various details of the integral-type non-local formulation, e.g. of the specific form of non-local averaging in the vicinity of a physical boundary, is studied and a physical explanation is provided. The numerical results are compared to experimental data for notched compact tension specimens, and conclusions are drawn for individual formulations. It is shown that the best agreement with experimentally observed trends is achieved if the notch is modelled as a layer of completely damaged material. Fitting of the size effects on both strength and fracture energy permits a unique identification of the model parameters.

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Fracture energy and fracture process zone

Cited by 235 publications

References 13 publications

Modified Disk-Shaped Compact Tension Test for Measuring Concrete Fracture Properties

Modified Disk-Shaped Compact Tension Test for Measuring Concrete Fracture Properties

Effect of meso‐structure on strength and size effect in concrete under tension

Size effect on fracture energy induced by non‐locality

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