Title: Rehabilitation of Exterior Beam-Column Joint by Geopolymer Mortar under Quasi-Static Loading

Author(s): Arshad Hussain Choudhury and Aminul Islam Laskar

Publication: Structural Journal

Volume: 120

Issue: 5

Appears on pages(s): 49-62

Keywords: beam-column joint; cyclic loading; geopolymer; removal and replacement method; seismically detailed

DOI: 10.14359/51738835

Date: 9/1/2023

Abstract:
Most of the studies conducted on the rehabilitation of reinforced concrete (RC) beam-column joints are on pre-1970 structures. Recently, it was reported that seismically designed beam-column joints might also suffer damage under lateral loading. On the other hand, there is an increasing interest among researchers to study the effectiveness of geopolymer as an alternative repair material. To date, no study has been conducted to examine the performance of geopolymer for the rehabilitation of seismically detailed beamcolumn joints following the removal and replacement method under cyclic loading. In the present investigation, two groups of exterior beam-column joints with different flexural strength ratios were rehabilitated with geopolymer mortar. For comparison, another set of beam-column joints (one from each group) were rehabilitated with cement mortar following the same rehabilitation technique and testing. Test results indicated that geopolymer rehabilitated specimens exhibited 20 to 21% higher initial stiffness, 19 to 22% higher displacement ductility, 24 to 37% higher cumulative energy dissipation, 14 to 17% higher initial equivalent viscous damping ratio, 21 to 26% higher ultimate equivalent viscous damping ratio at failure, and 10 to 14% lower damage index compared to specimens rehabilitated with cement mortar. However, irrespective of repair material, removal and replacement technique was only able to partially restore the cyclic performance of rehabilitated specimens.