Composite panels on the Museum of the Future. Photo Credit: CW
When we talk about where and how composites are used, construction typically does not rise to the top of the list, but it might be headed there. The global construction economy is among the largest in the world, and one of the largest consumers of resources and energy. It’s also one of the biggest polluters. These factors are combining to drive increased demand for sustainability across the board. Composites have a role to play.
According to “Global Construction 2030,” published by Global Construction Perspectives and Oxford Economics (London, U.K.), worldwide construction output will grow by 85% to $15.5 trillion by 2030. Most of this growth will be in the U.S., China and India. The McKinsey Global Institute (New York, N.Y., U.S.) reports that 36 million new housing units will be required in the world’s 20 largest cities by 2025. Other research from the construction industry shows that the construction industry is responsible for 23% of the United States’ air pollution, 40% of its water pollution and 50% of its landfill waste. In addition, the U.S. Green Building Council says buildings and construction projects are responsible for nearly 40% of global energy consumption every year.
The role of composites in construction is varied, ranging from window linneals and timber reinforcements to composites rebar and fiber-reinforced concrete. However they are used, the lightweighting, design flexibility and durability benefits of composites can help speed construction and improve a building’s sustainability score. Despite this, because composites are non-legacy materials, their adoption by architects has been incremental. But this is a growth market worth paying attention to.
Take, for example, the Museum of the Future, being constructed in Dubai, United Arab Emirates (UAE). The 78-meter high building houses seven floors within a torus-shaped shell that sits atop a three-story podium. The exterior facade of the torus comprises 1,024 fire-retardant (FR) composite panels. Clad with stainless steel, each panel is a unique 3D shape and integrates molded-in Arabic calligraphy. The flowing script forms poems that describe the vision for Dubai’s future by His Highness Sheikh Mohammed bin Rashid Al Maktoum, vice president and prime minister of the UAE and ruler of the Emirate of Dubai. They also serve as the building’s windows, casting daylight through the column-free interior and creating a dramatic effect at night via 14 kilometers of integrated LED lighting.
Two composite molds with a traditional wood mold. Concrete will be poured around all three to make a three-window facade frame for use in a building in Domino Park in Brooklyn, N.Y., U.S. Photo Credit: AES
In Brooklyn, N.Y., U.S., composites used in additive manufacturing helped speed construction of the 45-story One South First and the conjoined 10 Grand, located within Domino Park. These buildings include a complex concrete facade that required prefabrication of hundreds of concrete frames by Gate Precast (Jacksonville, Fla., U.S.). Gate engaged Additive Engineering Solutions (AES, Akron, Ohio, U.S.) for help to build the molds to shape the concrete frames. AES, which at the time had just acquired its first BAAM large-format additive manufacturing (LFAM) Oak Ridge National Laboratorymachine from Cincinnati Inc. (Harrison, Ohio), worked with (ORNL, Knoxville, Tenn., U.S.) , which also has a BAAM, to fabricate the forms. AES and ORNL split the work package, with AES producing 18 of the 37 molds. Each window frame mold measures about 5-6 feet wide, 9-10 feet tall and 16 inches deep and weighs about 500 pounds.
For part of its production, AES chose an LNP THERMOCOMP AM compound, a high-modulus, low-warp material based on ABS with 20% chopped carbon fiber reinforcement supplied by SABIC (Houston, Tex., U.S.). AES says it took the BAAM machine 8-10 hours to build each monolithic mold, followed by 4-8 hours of machining and finishing in a Quintax (Stow, Ohio, U.S.) CNC machine. The molds were sanded to the required dimensions, but not sealed. AES says the AM molds required fewer man-hours to fabricate, lasted significantly longer than the wood molds they replaced and allowed the contractor to stay on schedule.
Throughout the composites industry, there are signs of movement and positioning of materials aimed at construction. In May 2020, in response to the COVID-19 pandemic, Axia Materials (Hwaseong, South Korea), a polymer engineering and materials company, announced with its partners Staus (Busan, South Korea), a modular housing producer, and construction technology startup Dymaxon (Seoul, South Korea), the move-in ready Quarantreat Medical Isolation Studio (MIS) to fill this need anywhere in the world. Quarantreat MIS is a medical isolation studio featuring a hotel-class interior and an optional Negative Pressure Ventilation (NPV) system to control airborne pathogens. It is designed for rapid installation as a quarantine system for low-symptom or symptom-free COVID-19 infected or potentially infected patients. All the equipment necessary to live comfortably for a duration of a few weeks are fit into a compact 12.5-square meter (135 square feet) living compartment. This includes bathroom, furniture, HVAC with active air exchanger and Internet of Things (IoT) functionality; built-in TV, computer, mini-fridge and NPV options are available.
Rendering of CUBE building at TU Dresden and Hitexbau carbon fiber grid.Photo Credit: © Iurii Vakaliuk, HENN, TU Dresden and Hitexbau
In June, Technical University Dresden (TU Dresden) in Germany announced the onset of construction for its C³ tech demo house CUBE, locally known as Carbonhaus. TU Dresden claims the 220-square-meter, two-story building will be the world’s first building made entirely from carbon fiber-reinforced concrete.
In July, Purdue University (West Lafayette, Ind., U.S.) reported that its researchers have developed a lower-cost, sustainable and greener method for producing composite boards, a method that Purdue says is already seeing growing support from major industry players like high-pressure laminates distributor Wilsonart (Temple, Texas, U.S.), and CalPlant (Willows, Calif., U.S.), an agrifiber-focused company that produces rice straw-based medium-density fiberboard. The company says that fabrication of many composite boards requires the use of formaldehyde-based resin binders that are released into the home environment over time, posing significant health hazards since formaldehyde is a known carcinogen.
In September 2020, Deceuninck North America (Monroe, Ohio, U.S.) relaunched its existing Innergy Architectural Products (AP) with a new line of custom architectural solutions, including pressure plates, structural thermal struts, reinforcements and curtain wall components. The offering builds from Deceuninck's Innergy Rigid Thermal Reinforcements already used in window and door frame chambers for enhanced energy efficiency. In October, the University of Stuttgart (Stuttgart, Germany) Institute of Aircraft Design said it chose Adapa A/S’ (Aalborg, Denmark) adaptive mold technology in a project aimed at introducing composites in construction, with reduced material use through load-path-optimized composite structures and automated manufacturing to reduce CO2 gas emissions.
Compared to legacy materials like steel, aluminum, iron and titanium, composites are still coming of age, and only just now are being better understood by design and manufacturing engineers. However, composites’ physical properties — combined with unbeatable light weight — make them undeniably attractive.
The structural properties of composite materials are derived primarily from the fiber reinforcement. Fiber types, their manufacture, their uses and the end-market applications in which they find most use are described.
Fast-reacting resins and speedier processes are making economical volume manufacturing possible.