Corrosion-resistant wind turbine structure with thermoplastic FRP bars: an innovative corrosion-free reinforcement for concrete

Background and significance.

Corrosion of the internal steel reinforcement is a well-known issue when dealing with the maintenance and rehabilitation of land and offshore wind turbines. Particularly for offshore wind, corrosion of concrete and steel presents a significant challenge for infrastructure durability [1].  The use of fiber-reinforced polymer bars has gained popularity in the early 2000, and especially glass-FRP bars (or GFRP bars) in MRI hospital room additions is becoming commonplace.  Waterfront  construction,  top  mat reinforcement for bridge decks, various precast applications,  and ornamental and architectural concrete  has seen a more frequent use of GFRP bars in recent years.  Currently,  GFRP bars feature a thermosetting  resin that has been well studied.  The thermoplastic resin might offer some benefit in design and construction because it can be bent on-site as desired.  However,  there is no study available to support the use of  GFRP bars with thermoplastic resin. This project focuses on the bond behavior of the thermosetting and thermoplastic resin-based GFRP bars by systematic experimental and numerical models.

REU student involvement. 

REU students will participate in 1) Pull-out tests of GFRP bars embedded in concrete cylinders to measure the bond behavior under monotonic quasi-static loading, and 2) Pull-out tests under fatigue loading to measure the response of the bars [2]. REU students will also compare measurements to numerical modeling results of the bond behavior in pull-out tests. This project will address the feasibility of using a thermoplastic resin for GFRP bars.

References.

1. A. Mathern, C. von der Haar, and S. Marx, "Concrete support structures for offshore wind turbines: Current status, challenges, and future trends," Energies, vol. 14, no. 7, p. 1995, 2021.

2. A. S. Calabrese, T. D'Antino, P. Colombi,  C. Poggi,  and C. Carloni,  "Influence  of  the test set-up on  the bond behavior of frcm composites," Special Publication, vol. 345, pp. 185–195, 2021.