Traditional piles used for deep foundation, such as steel, concrete, and timber, are susceptible to corrosion and a reduction in structural capacity over time. This has led to the development of new materials like concrete-filled FRP piles (CFFP). CFFP is a composite pile filled with concrete and covered with a fiber-reinforced plastic (FRP) shell, providing non-corrosive reinforcement and protection to the concrete. As a result, CFFP is a highly promising candidate for implementation in various fields due to its structural advantages and necessity. Compared to traditional concrete piles, CFFP can be installed with less damage and a lower blow range due to its elastic modulus, damping ratio, and specific weight. The bearing capacity of a pile is influenced by various factors, including its stiffness, residual stress, and axial load resistance. Due to competitive pricing, glass fiber has been widely utilized, and there is a growing interest regarding carbon-fiber-reinforced concrete piles due to the excellent mechanical properties of carbon fiber. The remarkable stiffness and strength attributes of carbon fibers are evident in CFRP-confined piles, which present a notably wide range of load-bearing capacities, boasting an ultimate axial load capacity ranging from 500 to 4000 kN. Furthermore, CFFPs have been confirmed to have superior lateral load resistance compared to conventional piles, attributed to the reinforcement provided by FRP materials. Conventional piles face a challenge in that their structural characteristics deteriorate in the corrosive marine environment, with a projected lifespan of less than 20 years. In contrast, the service life of CFFPs is estimated to range from 50 to 75 years.

Feasibility of concrete-filled fiber-reinforced plastic piles for deep foundation: a comprehensive review on geotechnical and structural characteristics
    Abstract
    1 Introduction
    2 Types of composite piles
        2.1 Concrete-filled FRP piles (CFFP)
        2.2 FRP–steel-confined concrete (FSCC) columns
        2.3 Concrete-encased concrete-filled FRP (CCF) columns
        2.4 FRP-confined geopolymeric recycled aggregate concrete (GRAC) column
    3 Performance of composite piles
        3.1 Drivability of composite piles
        3.2 Vertical bearing capacity of piles
        3.3 Confinement effect
        3.4 Settlement
        3.5 Lateral deflection
        3.6 Durability
    4 Field project and applications of CFFP
    5 Conclusion
    Acknowledgements 
    References

• Haksung Lee(Reclaimed Land Agriculture Research Team, National Institute of Crop Science, Rural Development Administration, 181 Hyeoksin‑Ro, Wanju 181, Republic of Korea)
• Man‑Kwon Choi(National Institute of Horticulture and Herbal Science, Rural Development Administration, 1425 Jinham‑Ro, Haman 52054, Republic of Korea)
• Byung‑Joo Kim(Department of Carbon‑Nanomaterials Engineering, Jeonju University, 303 Cheonjam‑Ro, Jeonju 55069, Republic of Korea) Corresponding author