1 Evaluation of the bond performance in FRP-brick components re- bonded after initial delamination Bahman Ghiassi 1 , Jose Xavier 2 , Daniel V. Oliveira 3 , Arkadiusz Kwiecien 4 , Paulo B. Lourenço 5 , Boguslaw Zajac 6 ABSTRACT The bond behavior between Fiber Reinforced Polymers (FRPs) and masonry substrates has been the subject of many studies during the last years. Recent accelerated aging tests have shown that bond degradation and FRP delamination are likely to occur in FRP-strengthened masonry components under hygrothermal conditions. While an investigation on the possible methods to improve the durability of these systems is necessary, the applicability of different bond repair methods should also be studied. This paper aims at investigating the debonding mechanisms after repairing delaminated FRP- strengthened masonry components. FRP-strengthened brick specimens, after being delaminated, are repaired with two different adhesives: a conventional epoxy resin and a highly flexible polymer. The latter is used as an innovative adhesive in structural applications. The bond behavior in the repaired specimens is investigated by performing single-lap shear bond tests. Digital image correlation (DIC) is used for deeper investigation of the surface deformation and 1 Postdoctoral Researcher, ISISE, University of Minho, Department of Civil Engineering, Azurém, 4800-058 Guimarães, Portugal. Phone: +351 253 510 499, fax: +351 253 510 217, E-mail: bahmanghiassi@civil.uminho.pt 2 Research assistant, University of Trás-os-Montes and Alto Douro, UTAD, CITB, Quinta de Prados, 5000-801 Vila Real, Portugal, jmcx@utad.pt. LOME/INEGI, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. 3 Associate Professor, ISISE, University of Minho, Department of Civil Engineering, Azurém, 4800-058 Guimarães, Portugal. Phone: +351 253 510 247, fax: +351 253 510 217, E-mail: danvco@civil.uminho.pt 4 Associate Professor, Cracow University of Technology, Faculty of Civil Engineering, Cracow, Poland, E-mail: akwiecie@pk.edu.pl 5 Professor, ISISE, University of Minho, Department of Civil Engineering, Azurém, 4800-058 Guimarães, Portugal. Phone: +351 253 510 209, fax: +351 253 510 217, E-mail: pbl@civil.uminho.pt 6 Assistant Professor, Cracow University of Technology, Faculty of Civil Engineering, Cracow, Poland, E-mail: bz@limba.wil.pk.edu.pl