Abstract：Temperature is an important factor influencing the mechanical properties of glass fiber reinforced plastic(GFRP) material，and it should be considered sufficiently. Based on experiments，the mechanical properties of GFRP rebar at different environmental temperatures ranging from 20 ℃ to 120 ℃ are studied. The load is applied by MTS322 electro-hydraulic servo-controlled testing machine，and the test temperature is controlled by the circumstance box. Twenty six GFRP rebars are adopted in this test，which are 10 mm in diameter and 400 mm in the efficient pull-out length. The following conclusions can be drawn from the experiments. Firstly，during the loading process，white fleck cracks appear on the surface with hard noise caused by damage. The noise becomes louder with the load increasing. Flake crack in a big range is the main failure mode，and the rupture on a section is a rare occasion. Both are brittle failure modes. Secondly，the mechanical properties of GFRP rebar are sensitive to temperature. The ultimate tensile strength，the initial tensile Young¢s modulus，the yield strain and the ultimate elongation ratio all decrease with the temperature increasing，but the elastic modulus after tensile yield is reverse. Thirdly，the stress-strain relationship of GFRP rebar between 20 ℃–80 ℃ is bilinear. With the temperature increasing，the yield point reduces gradually. At the temperatures of 100 ℃ and 120 ℃，the stress-strain relationship is linear. By the analysis of experiment，considering thermal effect，the stress-strain relationship of GFRP rebars and the relationships between correlative parameters and the temperature have been established. A formula has been developed to calculate the ultimate tensile strength of GFRP rebar. The experimental results supply scientific foundations for the GFRP rebars¢ application at different temperatures.
