Utilisation of Ultra-High Performance Fiber Reinforced Concrete(UHPFRC) for Retroffiting - A Review

Abstract

Retrofitting has become a proven method for improving the load carrying capacity of existing concrete structural elements subjected to high mechanical loading, ageing or aggressive environments. Ultra-High Performance Fiber Reinforced Concrete (UHPFRC)is a relatively new generation of cement-based retrofitting material with a very high compressive strength and low permeability attributed to its tightly packed microstructure, also displaying excellent bonding ability with normal structural concrete. It has the potential to eliminate various problems caused by other retrofitting methods like FRPs or externally bonded steel plates as a result of the mismatch of stiffness with parent concrete. This study presents an overview of UHPFRC focusing on its properties, design, applications and challenges. The performance of UHPFRC concrete mix is greatly influenced by the type and degree of packing of its constituents in the cementitious matrix, necessitating the need for optimisation. Strength properties are very much higher when compared to that of conventional concrete alongside with increased durability aspects. The retrofitting technique showed an enhancement in the load carrying capacity of deteriorated structures. Therefore, UHPFRC can be considered as a practical solution to improve the sustainability of buildings and other infrastructural components. However, as a retrofit, there are some concerns regarding the loss of ductility. This broadens the need for methods to improve its ductility. This paper presents the state-of-art review of existing literature that deals with the retrofitting/rehabilitation of structures using UHPFRC. Altogether, the paper aims to expand the awareness regarding UHPFRC which was otherwise hindered, owing to limited design codes.