Results of notched beam (fracture) tests on a 60 MPa silica fume concrete at the ages of 4, 10, 31 and 232 days are presented. Fracture parameters at the different ages were obtained using the size effect and cohesive crack models, which indicate that the fracture resistance (toughness and energy) decreases and the brittleness increases with the age of the concrete. This trend is attributed to the increase in the strength of the hardened cement paste and the interfaces that leads to less bond cracking and more aggregate rupture, and consequently, to more brittle failure and lower toughening.

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