A simple fracture mechanical interpretation of size effects in concrete fracture toughness tests

Kim Wallin

    Research output: Contribution to journalArticleScientificpeer-review

    10 Citations (Scopus)

    Abstract

    Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is to make the specimen sense the crack as being longer than a0 + Δa. The fracture process zone causes thus an effective increase in the crack driving force and apparent fracture resistance. Here, a novel LEFM based estimate of the effective stress intensity factor and the effective crack growth at maximum load in a fracture mechanics test is used to obtain a simple power law approximation of the effective K–R curve. It is shown that it is applicable to the description of not only different size specimens, but also specimens with varying geometry. The method is based on a new theoretical estimate of the effective crack growth corresponding to maximum load.
    Original languageEnglish
    Pages (from-to)18-29
    Number of pages12
    JournalEngineering Fracture Mechanics
    Volume99
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Fracture toughness
    Concretes
    Cracks
    Crack propagation
    Displacement control
    Fracture mechanics
    Stress intensity factors
    Geometry

    Keywords

    • concrete fracture
    • fracture toughness
    • K-R curve
    • quasibrittle materials
    • size effect

    Cite this

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    abstract = "Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is to make the specimen sense the crack as being longer than a0 + Δa. The fracture process zone causes thus an effective increase in the crack driving force and apparent fracture resistance. Here, a novel LEFM based estimate of the effective stress intensity factor and the effective crack growth at maximum load in a fracture mechanics test is used to obtain a simple power law approximation of the effective K–R curve. It is shown that it is applicable to the description of not only different size specimens, but also specimens with varying geometry. The method is based on a new theoretical estimate of the effective crack growth corresponding to maximum load.",
    keywords = "concrete fracture, fracture toughness, K-R curve, quasibrittle materials, size effect",
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    A simple fracture mechanical interpretation of size effects in concrete fracture toughness tests. / Wallin, Kim.

    In: Engineering Fracture Mechanics, Vol. 99, 2013, p. 18-29.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - A simple fracture mechanical interpretation of size effects in concrete fracture toughness tests

    AU - Wallin, Kim

    PY - 2013

    Y1 - 2013

    N2 - Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is to make the specimen sense the crack as being longer than a0 + Δa. The fracture process zone causes thus an effective increase in the crack driving force and apparent fracture resistance. Here, a novel LEFM based estimate of the effective stress intensity factor and the effective crack growth at maximum load in a fracture mechanics test is used to obtain a simple power law approximation of the effective K–R curve. It is shown that it is applicable to the description of not only different size specimens, but also specimens with varying geometry. The method is based on a new theoretical estimate of the effective crack growth corresponding to maximum load.

    AB - Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is to make the specimen sense the crack as being longer than a0 + Δa. The fracture process zone causes thus an effective increase in the crack driving force and apparent fracture resistance. Here, a novel LEFM based estimate of the effective stress intensity factor and the effective crack growth at maximum load in a fracture mechanics test is used to obtain a simple power law approximation of the effective K–R curve. It is shown that it is applicable to the description of not only different size specimens, but also specimens with varying geometry. The method is based on a new theoretical estimate of the effective crack growth corresponding to maximum load.

    KW - concrete fracture

    KW - fracture toughness

    KW - K-R curve

    KW - quasibrittle materials

    KW - size effect

    U2 - 10.1016/j.engfracmech.2013.01.018

    DO - 10.1016/j.engfracmech.2013.01.018

    M3 - Article

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    SP - 18

    EP - 29

    JO - Engineering Fracture Mechanics

    JF - Engineering Fracture Mechanics

    SN - 0013-7944

    ER -