Co-authors​ :

 Mohammad Jawad BERRO (FRANCE), Juliana PREISNER (FRANCE), Eric LE GAL LA SALLE (FRANCE), Jean-Luc BAILLEUL (FRANCE) 

Composite materials are known to have a long history. They were first used in ancient Egypt and Mesopotamia as combinations of straw and mud to create strong and sturdy buildings. With continuous development, composites have become more complex and more diverse. They still share some remarkable properties that make them preferable and versatile. Thanks to their light weight, high stress resistance and high rigidity, these materials are widely used in many industrial and commercial applications. The value of the composite market attained 90 billion dollars back in 2019. Upon this increasing usage, the market value is estimated to increase by 7.6% reaching 160 billion dollars in 2027. As a result, huge amounts of waste are produced. It is estimated that in France alone, at least 10,000 tons of exploitable composite waste are produced annually. Another 200,000 tons of wind blade waste are predicted between 2020 and 2034. This poses a serious demand on current recycling technologies which are classified into three main categories: mechanical, thermal and chemical. These approaches present multiple disadvantages such as high cost, loss of material properties and safety risks. That said, it is necessary to perform intensive research works aiming to develop new, efficient methodologies and to improve current ones. The current works at Icam Ouest and LTeN are part of the European project RECREATE which aims to improve the circularity and reuse of composite materials. Their objective is to study a new process for reshaping and reusing large end-of-life glass fiber-reinforced polyester (GFRP) parts from boats and wind turbines. This process has been studied recently by Nouigues at Icam Ouest. It uses hot rolling to transform curved composites into flat parts with minimal or negligible loss of their mechanical properties. Then, they can be used in furniture, public transport and building facades. Studying the process involves thorough material characterization as a first step. Mechanical properties such as strength, deformation and Young’s Modulus under tensile and flexural stresses are determined. Viscoelastic behavior, directly linked to the matrix, is studied in relaxation and creep allowing to monitor the material’s response under sustained deformations or stresses. Shape recovery after reforming is an important factor to study as it is part of the process’s efficiency and the final product’s field of application. High friction during the process poses an equivalent great interest in addressing the composite’s tribological properties. These would provide the necessary information and guidelines for realizing hot rolling tests that comply with the material limits.