Fracture behaviour of concrete containing waste tire and waste polyethylene terephthalate: An sustainable fracture design

•Fracture properties of NC and RC were obtained using two different methods.•Results showed with decrease of PET content the fracture energy decreases.•Size effect can predict the peak load with a good precision for NC and RC beams.•NC and RC ductility increases with increase of PET content. This paper illustrates the results of an experimental investigation on fracture characteristics and ductility of normal concrete (NC) and rubberized concrete (RC), involving the tests of 128 three-point bending specimens with different polyethylene terephthalate (PET) aggregate volumes. Generally, the parameters were analyzed by the size effect method (SEM) and boundary effect method (BEM). The results showed that with increase of PET aggregate volume from 0% to 15%, (a) in a sustainable approach the fracture energy increases which is due to the change in fractal dimensions, (b) behavior of concrete specimens approaches strength criterion, (c) the fracture process zone measurement, Cf, in SEM and a∞∗ in BEM, which is deemed as an index of brittleness, increases, (d) the brittleness number decreases by 35.2 and 22.5% for NC and RC, respectively. Also, a suitable relation with good accuracy is developed for fracture energy of NC and RC at different PET aggregate volumes, which may be an effective step towards development of design provisions for sustainable NC and RC members.