POSSIBLITIES OF USING UHPC AS A REPAIR MATERIAL

More and more buildings need to be repaired and strengthened, both for durability and for the effects of natural disasters such as earthquakes. The repair material should ensure compatibility with the substructure materials and contribute to their improvement. The continuous development of materials has led to their excellent properties and application possibilities. In addition, the new generation of materials offers more environmentally friendly solutions, which is certainly in line with repair as part of sustainable development. In an effort to meet all these requirements, the use of mortars with exceptional properties and environmental efficiency can be the key to solving repair works. Materials such as ultra-high performance concrete (UHPC) are characterised by exceptional mechanical and durability properties. In its usual composition, it contains large amounts of cement, which can be reduced by using waste materials to improve its environmental performance. One of the properties of UHPC worth highlighting is its toughness, which is achieved through the use of fibres that ensure a cement composite with ductile behaviour. Therefore, this paper presents a general overview of UHPC and the possibility of its application as a repair material. The evaluation of UHPC as a repair material is based on the studies carried out. These are divided into tests of interfacial properties, which include bond strength, microstructure, and permeability. The influence of additional cementitious materials on the interfacial microstructure is presented. Finally, the importance of fibres and the potential self-healing effect of UHPC in repair are highlighted and opportunities for new studies are identified.