EXPERIMENTAL INVESTIGATION ON AXIAL COMPRESSION BEHAVIOR OF RC COLUMNS STRENGTHENED WITH HDC AND RPC JACKETS

In order to study the axial compressive behavior of reinforced concrete (RC) columns strengthened with high ductile concrete (HDC) and reactive powder concrete (RPC) jackets. Eight RC square columns were prepared; four of them were jacketed with HDC, three with RPC and one control specimen. Axial compression tests were carried out to investigate the influence of the material types, the loaded ways and the reinforcement arrangements of the jackets on test results. The failure modes, bearing capacity, load-displacement curves and strain development of specimens are analyzed. Test results show that the failure modes of strengthened columns have been improved. The jackets reinforced with steel mesh exhibit good integrity. The interface between jacket and concrete has reliable bond strength. Thusly, the bearing capacity and deformation capacity of all strengthened specimens have been improved. The bearing capacity of strengthened specimens is increased greatly, whose jackets are directly loaded. Based on the analysis of the strengthening mechanism of jackets, the formulas for calculating the bearing capacity of the strengthened specimens is developed, in which the stress lag of jackets is considered. And the calculating results are in a good agreement with the experimental results.