*Article* **Influence of Fiber Addition on the Properties of High-Performance Concrete**

**Szymon Grzesiak 1, Matthias Pahn 1,\*, Milan Schultz-Cornelius 1, Stefan Harenberg <sup>2</sup> and Christoph Hahn <sup>3</sup>**

	- christoph.hahn@mbcc-group.com

**Abstract:** High performance fiber-reinforced concrete (HPFRC) has been frequently investigated in recent years. Plenty of studies have focused on different materials and types of fibers in combination with the concrete matrix. Experimental tests show that fiber dosage improves the energy absorption capacity of concrete and enhances the robustness of concrete elements. Fiber reinforced concrete has also been illustrated to be a material for developing infrastructure sustainability in RC elements like façade plates, columns, beams, or walls. Due to increasing costs of the produced fiber reinforced concrete and to ensure the serviceability limit state of construction elements, there is a demand to analyze the necessary fiber dosage in the concrete composition. It is expected that the surface and length of used fiber in combination with their dosage influence the structure of fresh and hardened concrete. This work presents an investigation of the mechanical parameters of HPFRC with different polymer fiber dosage. Tests were carried out on a mixture with polypropylene and polyvinyl alcohol fiber with dosages of 15, 25, and 35 kg/m<sup>3</sup> as well as with control concrete without fiber. Differences were observed in the compressive strength and in the modulus of elasticity as well as in the flexural and splitting tensile strength. The flexural tensile strength test was conducted on two different element shapes: square panel and beam samples. These mechanical properties could lead to recommendations for designers of façade elements made of HPFRC.

**Keywords:** high performance fiber reinforced concrete (HPFRC); polypropylene fiber (PP); polyvinyl alcohol fiber (PVA); compressive strength; residual flexural strength; splitting tensile strength
