Table 5 Summary of durability studies for GFRP.

Jin et al²⁹.

Alkaline solution + sustained load

180 days (accelerated)

~ 56% (worst case)

Loss increases with sustained stress and alkalinity.

Tu et al³⁰.

Simulated seawater & concrete pore solution

180 days (lab)

70–90%

Good retention under moderate marine conditions.

Feng et al³¹.

Alkaline + elevated temperature

180–270 days (accelerated)

45–60%

Larger diameter and higher T accelerate degradation.

Myers et al³².

In-service bridge cores

17 years (field)

~ 98% (≈ 2% loss)

Excellent long-term performance in real structure.