Size Effect on Failure of Concrete Beams With and Without Steel Fibers

The experimental program is designed to verify and calibrate the size effect theory. Test specimens made of notched beams are tested under four-point bending. The beams are geometrically similar in two dimensions, and the thickness of all beams is 40 mm. Beams with three different heights (40, 80, and 160 mm) with length/height ratios of 5 and size ranges 1:2:4 are tested. Maximum aggregate size is 15 mm. To start the fracture band, the beams are notched with a depth of 25% of the beam height. Additionally, fracture energy Gf, process zone length cf, and crack tip opening displacement deltac are defined by the size effect law that has been obtained.