Lessons learnt during experimental study of Bond Slip behavior of GFRP bars MS rebars

Abstract

Bond strength of concrete-rebar composite directly influences load carrying capacity of reinforced concrete
structures. It becomes more crucial when the structure is exposed to harsh environmental conditions including elevated temperatures, chemical, or mechanical loading. A research program was designed to evaluate the bond slip behavior of mild steel rebars and glass fiber reinforced polymer bars GFRP when subjected to above three conditions In this investigated a total of 18 specimens were prepared. Six specimens, three of both categories were directly subjected to pullout test. A further six specimens, three of each category were first exposed to acidic solution (HNO3 solution) of 2pH then subjected to pullout test. Then six specimens, three of each category were first exposed to elevated temperature of 800 ℃ in an electric furnace then subjected to pullout test. However in this paper discusses pull out test of bars only. This study concluded that GFRP bars lost their integrity at high temperature due to resin damage. Further while performing pullout tests ends of GFRP bars are crushed. It was noticed at if bond between concrete and steel is intact failure initiates with split type crack in concrete cubes.