The Fracture Toughness of Fibre Concretes

  • Kenneth Lai-Wing

    Student thesis: Doctoral Thesis


    This thesis presents experimental and numerical results on the application of Fracture Mechanics to concrete materials. In the experimental work, a study of the general properties of plain and fibre-reinforced concrete has been carried out with particular emphasis on Mode II as well as Model failure. A numerical study of the test specimens used in the experimental work has been carried cut using constant strain triangular elements.

    Three new fracture toughness tests are proposed. Two of these tests are based on the traditional standard concrete quality control specimens. The tests are relatively easy to apply requiring a minimum of specimen preparation.

    The fracture toughness values have been determined from the finite element results. Stress intensity factor is readily determined from a knowledge of the load at failure and the configuration of the test specimen.

    The effect of the test specimen geometry has been investigated. The results indicate that the fracture toughness value was independent of the proposed specimen geometry. A good correlation of results was obtained in the split cube specimens with the coefficient of variation generally within ten percent.

    The effect of varying the modulus of elasticity in concrete was also investigated. The results show that Kic is dependent on the modulus of elasticity value for the Finite Element Analysis used in this work.

    The tests developed in this study have been applied to polypropylene fibre reinforced concrete and glass fibre reinforced cement composites. The effects of varying quantities of fibre on the stress intensity factor have been investigated.

    Conclusions from this project and possible future work are summarised in the last chapter.
    Date of Award1982
    Original languageEnglish
    Awarding Institution
    • Polytechnic of Wales

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