A three-company partnership is paving the way for circular FRP composites in the first 3D-printed recycled plastic material footbridge. Image Credit: Travel Addicts/Shutterstock.com
Fiber-reinforced plastic (FRP) composites are increasingly being adopted as structural materials when building modern urban infrastructure. In a partnership with three Dutch companies, DSM, Royal HaskoningDHV and CEAD, the city of Rotterdam in the Netherlands has showcased the use of circular FRP composites in the world's first 3D-printed footbridge using recycled plastic material.
FRP composites were historically developed and utilized extensively in aerospace, defense, and marine industries. During the last 30 years, their application has been gradually expanding into various industrial sectors such as transport, energy production, and construction due to the numerous advantages the FRP composites have to offer.
Compared to the traditional construction materials, such as wood, steel, and concrete, the FRP composites provide better corrosion and weather resistance, higher strength at a reduced weight, and better dimensional stability, while requiring lower maintenance at the same time.
The construction industry has the potential to become the largest market for FRP composites in the future, benefiting from the improved design flexibility, ease of transportation and installation, and long-term durability of the composite-made civil infrastructure.
Circular Composites Gain Interest from the Industry
Because of the inherent heterogeneity of the polymer matrix and the reinforcement fibers, the FRP composites exhibit poor recyclability. These materials are usually down-cycled as fuel for power generation with little recovery of materials such as reinforcement fibers.
There is a current shift from the 'take-make-dispose' approach, where materials are extracted, manufactured into products, and discarded at the end of their life, towards a more sustainable circular economy model. The circular approach aims to keep resources in use for as long as possible, extracting the maximum value from them, and requires the development of innovative manufacturing and end-of-life treatment methods.
Dutch Innovation Creates 3D-Printed FRP Footbridge
Three Dutch companies at the forefront of the advanced engineering and materials technology joined forces in a breakthrough development that revolutionizes bridge construction and design.
DSM, Royal HaskoningDHV, and CEAD have designed the first lightweight 3D-printed FRP footbridge prototype using a circular composite material.
The innovative pedestrian bridge will be installed in Rotterdam's Kralingse Bos Park and features glass-filled thermoplastic material that combines continuous glass fibers during the 3D printing process.
This unique combination of advanced materials and fabrication methods ensures high strength and extreme versatility and sustainability of the final structure.
While the idea of composite bridges and walkways is not new, with hundreds constructed and installed across North America, Europe, and China, up until now, they have all been fabricated using traditional plastic molding methods.
Employing additive manufacturing methods, on the other hand, opens up possibilities for reusing the building materials and feeding them back into the economy in a high-value form.
Read more: 3D Printers and 3D Printing Equipment, Materials and Accessories
Industrial Partnership Promotes Sustainable Manufacturing
As a global science-based company operating across a broad spectrum of activities, such as nutrition, sustainable living, and engineering materials, DSM maintains a significant footprint within the additive manufacturing sector. The company collaborates with partners across the 3D printing value chain, aiming to expand the capabilities of its additive manufacturing products.
In May 2019, DSM partnered with CEAD, a Netherlands-based large-format 3D printer supplier specialized in FRP-based additive manufacturing technologies, for the development of new materials, tools, and end-use applications compatible with the fused granulate fabrication methods (a type of material extrusion-based 3D printing).
At the same time, DSM and Royal HaskoningDHV, a global engineering and project management company based in Amersfoort in the Netherlands, jointly developed workflow software for additive manufacturing applications that enables the manufacturers to optimize material choice, 3D printing performance, design topology, and many other factors.
A Circular Composite Footbridge as an Advanced Technology Demonstrator
In their latest joint project, the three industrial partners combine their technological know-how to create a first-of-its-kind circular composite footbridge. Using DSM's Arnite composite material, a recyclable glass-filled thermoplastic polyester, in conjunction with CEAD's proprietary continuous fiber additive manufacturing (CFAM) process allows the fabrication of highly filled composite parts with enhanced mechanical strength and thermal stability, comparable to those of injection-molded parts.
The innovative 3D printing process takes place in CEAD's flagship large-format 3D printer, the CFAM Prime, with a printing volume of 4x2x1.5 m that can handle large and complex parts.
The robotic 3D printer's extruder processes almost all existing thermoplastics with maximum processing temperatures of 400 °C. It combines the extrusion of granules with pre-impregnated continuous fiber filaments to print high-performance FRP components.
Smart Design for the Next-Generation Bridges
The design of the footbridge itself, developed by Royal HaskoningDHV, brings a significant reduction in cost and construction time by assembling the bridge from large-scale parts, and by optimizing the printing process and amount of FRP composite used. The designers also included sensors in the bridge to help optimize the bridge's maintenance and extend its life span.
Most importantly, the novel 3D printing method helps to provide a sustainable construction approach with minimal material waste. All bridge components can be recycled at the end of their life by grounding up (granulation). The resulting circular FRP composite material can be reused to 3D-print the same high-value components with the same properties and function.
First Step towards Circular Urban Infrastructure
The city of Rotterdam plans to install the 6.5 meter-long smart circular composite footbridge by the end of 2020. The use of circular composite materials aligns with the city's environmental philosophy that aims to reduce the carbon footprint and enhance the sustainability of the urban infrastructure.
The realization of this project is an essential step towards the development of next-generation bridges that are easier to manufacture, require lower maintenance and lifecycle costs, and ensure circularity and sustainability of the source materials.
References and Further Reading
S. Moore (2020) World's First 3D-printed FRP Footbridge Paves Way for Circular Composites [Online] www.plasticstoday.com Available at: https://www.plasticstoday.com/3d-printing/worlds-first-3d-printed-frp-footbridge-paves-way-circular-composites (Accessed on 17 August 2020).
DSM (2020) World's first 3D printed fiber-reinforced plastic footbridge paves way for circular composites. [Online] www.dsm.com Available at: https://www.dsm.com/corporate/news/news-archive/2020/2020-07-07-worlds-first-3d-printed-frp-footbridge-paves-way-for-circular-composites.html (Accessed on 17 August 2020).
K. Laird (2020) Rotterdam will see the installation of the world's first 3D printed FRP footbridge. [Online] www.sustainableplastics.com Available at: https://www.sustainableplastics.com/news/rotterdam-will-see-installation-worlds-first-3d-printed-frp-footbridge (Accessed on 17 August 2020).
A. Essop (2019) DSM, Royal HaskoningDHV and CEAD Design "World's First" Lightweight 3D Printed Bridge. [Online] www.3dprintingindustry.com Available at: https://3dprintingindustry.com/news/dsm-royal-haskoningdhv-and-cead-design-worlds-first-lightweight-3d-printed-bridge-161154 (Accessed on 17 August 2020).
P. Hanaphy (2020) Sustainable 3D Printed Footbridge to be built in Rotterdam Using DSM Thermoplastics. [Online] www.3dprintingindustry.com Available at: https://3dprintingindustry.com/news/sustainable-3d-printed-footbridge-to-be-built-in-rotterdam-using-dsm-thermoplastics-173243/ (Accessed on 17 August 2020).
M. Zoghi (2015) Applications of the advanced FRP composites to restore and improve urban infrastructure, QScience Proceedings (Engineering Leaders Conference 2014), 54 Available at: http://dx.doi.org/10.5339/qproc.2015.elc2014.54
S. H. R. Sanei and D. Popescu (2020) 3D-Printed Carbon Fiber Reinforced Polymer Composites: A Systematic Review. J. Compos. Sci., 4, 98. Available at: https://doi.org/10.3390/jcs4030098