Nanosilica　powder　was　added　to　modify　the　properties　of　epoxy　binder.　Two　types　of　modified　epoxy　resin　binder　[crack　glue　and　fiber-reinforced　plastic　(FRP)　glue]　are　developed　to　repair　cracks　and　to　glue　fiber　fabrics　to　the　concrete　surface,　respectively.　Bonding　strength　of　FRP　concrete　interface　is　tested,　the　flexural　strength　test　for　FRP-strengthened　cracked　concrete　is　conducted,　and　the　effects　of　FRP　dimensions,　concrete　strengths,　and　types　of　premade　crack　and　epoxy　binder　on　strengthening　are　analyzed.　Nanosilica　powder　greatly　improves　the　ductility,　strength,　and　workability　of　epoxy　binders.　Effective　bonding　between　FRP　and　concrete　can　be　achieved　by　nanomodified　FRP　glue.　Nanomodified　crack　glue　is　able　to　repair　concrete　containing　cracks　without　diminishing　concrete　capacity.　The　failure　regions　are　beyond　the　premade　cracks.　The　ultimate　capacity,　ultimate　displacement,　and　fracture　energy　of　cracked　concrete　are　significantly　improved　by　strengthening　with　crack　glue　and　FRP.　(C)　2016　American　Society　of　Civil　Engineers.