RETROFITTING OF RC BEAMS USING ULTRA HIGH PERFORMANCE FIBER REINFORCED CONCRETE

Abstract

Shear deficient structures have been strengthened or repaired by using various methods, e.g., external pre-stressing, shotcreting, steel plate bonding, polymer impregnation, fiber reinforced polymers (FRPs). But there were problems with each of the above techniques as the use of FRP gives sudden failure due to de-bonding, steel plates got corroded after some time and several losses in the case of external pre-stressing. To overcome all the above problems faced in different retrofitting techniques, a new cementitious material with ultra high performance characteristics like very high compressive strength (above 110 MPa), high tensile and flexural strength due to the addition of fibers, very less permeable and high workability i.e. UHP-FRC came into existence. In the present study, shear deficient RC beams initially stressed to a prefixed percentage, i.e. 60% of the ultimate failure load are retrofitted using UHP-FRC. Retrofitting is done using side face retrofitting. From the study it is seen that the ultimate load carrying capacity of RC beams retrofitted with UHP-FRC is significantly increased with side face retrofitting. Moreover, this technique also increased the ductility and energy absorption of RC beams which resulted in the usefulness of UHPFRC as a retrofitted material.