UHPC in Czechia – Research and applications

Ultra-high-performance concrete (UHPC) is in this paper always considered as a cement composite material made of local constituents and reinforced with high strength steel fibres. Extensive research was carried out in order to understand its behaviour under different loading conditions. Successful tests enabled its application in various structures. Footbridges are structures where UHPC can be successfully applied. The next step of research works was focused on rehabilitation of existing concrete structures. Promising research results led to rehabilitation of a large bridge in Prague using UHPC. The Technical specifications prepared by the Czech Concrete Society will be soon approved by the Ministry of Transport. Then the new applications for Highway and Railway administrations are expecte

Influence of polyethylene and stainless steel fibres on compressive and tensile behaviour of high-performance fibre-reinforced cementitious composites

High-Performance Fibre-Reinforced Cementitious Composites (HPFRCC) is a class of materials studied extensively for applications in structural rehabilitation of existing structures and in design of new structures. These materials have high mechanical strength, pseudo-strain-hardening behaviour and low porosity due to a highly dense microstructure of the cementitious matrix. Furthermore, they guarantee great durability by adding microfibres in the proper ratio, which limits the crack opening. This paper deals with the mechanical properties assessment of HPFRCC mixtures designed with locally available materials. Different HPFRCC mix designs were considered with a very compact cementitious matrix reinforced with two different types of microfibres: high-density polyethylene fibres and hooked stainless steel fibres considering 1% or 2% of the volume contents. The influence of the fibre contents on the compressive and tensile strengths, the strain-hardening performance and the fracture energy are discussed