The effect of aggregate type on fracture energy in steel fiber concretes

Demolition wastes generated in the context of urban regeneration constitute a serious waste source and the disposal of these wastes has started to attract the attention of the researchers. Civil engineering researchers work on the use of demolition wastes in concrete production. This is a very important issue in order to create beneficial transformation mechanisms and it is necessary to carry out comprehensive studies about it for sustainability. The studies on the production of concrete with the use of recycled aggregates are mainly about the production of concrete with certain strengths and the determination of the basic engineering properties of these concretes. Response to specific expectations from these recycled aggregate concrete (ductility, etc.) in structural systems has not been fully established yet. The aim of this thesis is to investigate the effect of aggregate type on fresh and hardened concrete properties and fracture energy in steel fiber concretes. For this purpose, C35 strength class steel fiber reinforced concretes were produced by using recycled aggregate, crushed stone aggregate and natural aggregate. Firstly, fresh and hardened properties of concrete were determined. Then, using concrete produced with all aggregate types, notched beam samples were produced in order to reveal the fracture energies of steel fiber reinforced concrete. The produced notched beams were subjected to a three-point bending test after 28 days of curing and the fracture energy data of the beams were determined by using parameters such as bending load, the geometry of beam, notch opening amount in the beam, amount of collapse in the beam. As a result, the fracture energy data obtained from steel fiber reinforced concrete containing recycled aggregate, crushed stone aggregate and natural aggregate were evaluated comparatively.