Vol.25, No.3, 2025, pp. 419–426
https://doi.org/10.69644/ivk-2025-03-0419

One of the important criteria in the concrete structure design is to investigate the flexural behaviour of concretes. The flexural strength and fracture energy are the resulting parameters from the bending test of concrete samples. In order to investigate and improve the concrete specifications, two pozzolans and also two types of fibres have been used in concrete samples. The behavioural effect of each material (zeolite pozzolan and silica fume, steel fibres, and glass) and also their effect have been evaluated simultaneously. One of the new subjects over the last years regarding the concrete behaviour is to consider the preloading in fibre concretes in this study. The results demonstrate that increasing fibres in designs without pozzolan bring about different results. In these designs, increasing glass fibres did not significantly increase flexural strength, while increasing steel fibres increased flexural strength. Besides, in designs with combined preloading, the difference in results decrease by reducing 2 % of silica fume. Accordingly, it can be concluded that zeolite pozzolan plays a more active role in curing cracks for short periods. In assessing the fracture energy of samples, the samples containing 1 % steel fibres indicate greater fracture energy.

Keywords: • preloading • steel and glass fibres • mechanical behaviour • zeolite • silica fume