Performance recovery of a repaired earthquake-damaged ternary composite geopolymer recycled concrete structure: Shake table tests

Addressing the urgent need for sustainable construction materials due to the high carbon footprint of the cement industry, geopolymers have been identified as a viable alternative to traditional cementitious materials in concrete structures. In this context, this study focuses on the reparability of the geopolymer recycled concrete structure. Specifically, repair work was undertaken on a previously damaged, half-scale, 2-story ternary composite geopolymer recycled concrete structure containing recycled fireclay brick aggregates (GRA-RFBAC) frame structure. The repairs utilized epoxy resin to restore the structural performance and the structure was subjected to a series of ground motions through shake table testing. The performance of the repaired structure was compared to that of the original structure before repairs. It was found that the repaired structure exhibited a 45 % functionality loss, better than the original's 50 % functionality loss under the same conditions. Additionally, the repaired structure showed less visible damage, particularly less spalling. The repaired structure recovered structural performance even at moderate seismic levels. Although the repairs led to more uniform residual drift ratios, they did not fully restore the original structure's stiffness. The repaired structure maintained comparable base shear forces and drift ratios to the original, despite a 23.6 % base shear increase in the original during the aftershock. Moreover, reparability evaluation methods were developed based on the maximum inter-story drift ratio and the residual inter-story drift ratio. These methods could evaluate the reparability probabilities of GRA-RFBAC structures at different performance levels based on nonlinear time-history analysis.