THE DURABILITY OF GLASS FIBER REINFORCED COMPOSITE REBARS IN SALT LAKE HIGH AND COLD AREA¹⁾

The durability tests of glass fiber (GFRP) and GFRP-reinforced steel rebars are carried out under the action of multiple environmental factors in Salt Lake Area. The environmental types and the action time influence the ultimate tensile strength, the elastic modulus and the ultimate strain. It is shown that the tensile strength of the GFRP rebars and the GFRP steel rebars decreases gradually with the increase of the corrosion cycles, the freeze-thaw cycles and the dry-wet cycles in Salt Lake, and the brine under the coupling of multiple factors, but the tensile strength reduction of the GFRP rebars is small, the ultimate tensile strength reduction of GFRP steel rebars is not significant, especially when the GFRP steel rebars is put in Salt Lake for more than 90 days. With the brine and more than 150 cycles of freeze-thaw, the yield strength of the GFRP bars is almost non-existent and close to the ultimate tensile strength, and the elastic modulus of the GFRP bars decreases and then increases with the increase of age, however, the elastic modulus of the GFRP rebars decreases gradually, which is not very large in comparison with the GFRP rebars under various coupling factors, and the ultimate tensile strength and the elastic modulus of the GFRP rebars under various coupling factors are smaller than those under a single factor, and the relationship with the corrosivity is: Salt Lake Brine + dry-wet cycle + freeze-thaw coupling > Salt Lake Brine + dry-wet cycle > freeze-thaw > Salt Lake Brine.