Flexural Strength of Thin Slabs Made of UHPFRC

Abstract

This paper focuses on the determination of the flexural strength of thin slabs made of the Ultra High Performance Fiber Reinforced Concrete (UHPFRC). The load-bearing capacity in bending of elements reinforced only with steel fibers (used as a scattered reinforcement) is primarily influenced by the orientation and distribution of the fibers. A size-effect occurs by these elements. Some special bending tests were executed within the development of precast bridge deck segments for an innovative timber-concrete composite bridge system. The bending tests were executed on the slab strips under similar boundary conditions as by the bridge deck segments. The slab strips of various thickness of 40, 50, 60, 70 and 80 mm were tested in 4-point bending tests with span 1900 mm and in 3-point bending tests with span 600 mm. Half of the test specimens was tested in casting position, the other half was tested upside down. The obtained values of the flexural strength were compared to values from reference bending tests of the beams 150 x 150 x 700 mm, 100 x 100 x 400 mm and 40 x 40 x 160 mm. An influence of the different size of the tested specimen, of the slab thickness, of the span size and of the positioning of the slab with respect to the direction of casting on the flexural strength are evaluated. The experiments are further supported by numerical simulation.