The present paper proposes a method to calculate Mode I plane-strain fracture toughness of concrete, by taking into account the possible crack deflection (kinked crack), even in the case of a far-field Mode I loading. As a matter of fact, during fracture extension, cracks may deflect as a result of microstructural inhomogeneities inside the material. Concrete is an inhomogeneous mixture due to aggregates embedded in the cementitious matrix, but additional inhomogeneities may be represented by fibres. Firstly, a two-parameter fracture model based on Mode I analytical expressions of the linear elastic fracture mechanics is employed. Then, in order to take into account the possible crack deflection as a result of the above inhomogeneities, a modified version of such a model is here discussed. Three-point bending tests on both plain concrete specimens and concrete specimens reinforced with micro-synthetic polypropylene fibrillated fibres are experimentally performed, and the modified model is applied.

Mode I fracture toughness of fibre-reinforced concrete by means of a modified version of the two-parameter model

RONCHEI, Camilla;
2016

Abstract

The present paper proposes a method to calculate Mode I plane-strain fracture toughness of concrete, by taking into account the possible crack deflection (kinked crack), even in the case of a far-field Mode I loading. As a matter of fact, during fracture extension, cracks may deflect as a result of microstructural inhomogeneities inside the material. Concrete is an inhomogeneous mixture due to aggregates embedded in the cementitious matrix, but additional inhomogeneities may be represented by fibres. Firstly, a two-parameter fracture model based on Mode I analytical expressions of the linear elastic fracture mechanics is employed. Then, in order to take into account the possible crack deflection as a result of the above inhomogeneities, a modified version of such a model is here discussed. Three-point bending tests on both plain concrete specimens and concrete specimens reinforced with micro-synthetic polypropylene fibrillated fibres are experimentally performed, and the modified model is applied.
Fibre-reinforced concrete; fracture toughness; micro-synthetic polypropylene fibrillated fibres reinforced concrete; two-parameter fracture model
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/304685
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