Research on coupled erosion damage model of FRP bonded concrete beams subjected to Lemaitre assumption

Abstract In cold regions, the coupling of freeze–thaw cycles and sulfate frequently impairs the performance of FRP‐bonded concrete, resulting in a shortened service life. Carbon fiber polymer (CFRP) and glass fiber polymer (GFRP) are used to paste pre‐cracked concrete beams in the experiment, and three unfavorable environments are created: freeze–thaw cycle, 10% sulfate solution erosion, and coupling erosion. This paper investigates the durability performance of FRP bonded beams using microscopic, mechanical and dynamic modulus of elasticity tests, as well as post‐erosion damage values and finite element modeling. After 400 h of coupled erosion, sulphate erosion and freeze–thaw cyclic erosion environments, the strength of the CFRP bonded beams was reduced by 66.3%, 14.6% and 42.0% and the GFRP bonded beams by 67%, 21.9% and 52.3% respectively. The results show that single sulphate attack does not cause significant damage to the beams, but it can exacerbate the damage caused by freeze–thaw cycles. A coupled damage model based on the Lemaitre strain equivalence assumption predicted the actual coupled damage of the specimens. The finite element model can accurately predict the damage and strength of the bond surface under loading. Highlights The durability performance of CFRP and GFRP adhered pre‐cracked concrete beams Microscopic, mechanical, and dynamic elastic modulus tests are used Freeze–thaw erosion environment in 10% mass fraction sulphate solution Coupled damage models for coupled salt and freeze–thaw cycles are developed FRP ‐reinforced pre‐cracked beams subjected to erosion are simulated with ABAQUS