Recycled plastic 3D printed beams replace reinforced concrete
A team from the Polytechnic University of Valencia (UPV) has developed an alternative to the reinforced concrete beams used in the construction sector. Using additive manufacturing, they designed beams from recycled plastic. The result is a drastic reduction in weight, since they weigh 80% less than current solutions, which considerably facilitates their transport and reduces the energy required for their assembly. The various 3D printed components forming the beam can be put together as easily as LEGO bricks.
Very popular in the construction industry, reinforced concrete is, as the name suggests, composed of concrete and metal, most often steel. It is therefore a composite material that can withstand traction and compression and is able to withstand significant loads. However, it is a material which remains heavy to transport because the presence of steel considerably increases the weight of the beam. The researchers therefore tried to reduce this constraint as much as possible and worked for 3 years on a 3D printing project. José Ramón Albiol, professor at the Technical School of Building Engineering at the UPV (ETSIE), adds: “Our goal was to offer an alternative to current reinforced concrete beams. These are made using profiles built to the length of the room, which requires expensive installation and are difficult to transport.. “
3D printed beams inspired by human bones
Researchers remain rather discreet about the 3D printing process used; we only know that they preferred recycled plastic to reduce the ecological footprint, and that they were inspired by the shape of the bone to design their 3D models. The objective was to reproduce the structure of the epiphysis, the terminal part of the bones: it is made up of several layers which give significant rigidity while remaining fairly light. Thanks to additive manufacturing, researchers were able to mimic this honeycomb structure and place the material where it was needed.
The result is a reduction in the total weight thanks to the use of plastic instead of steel, but also thanks to a better distribution of the material. José Ramón Albiol continues: “It is a honeycomb structure, which reduces the amount of plastic used – and therefore its weight – while maintaining structural rigidity. This is what we transferred to these revolutionary beams, especially their profiles. It is a very intelligent natural system and its reproduction in these beams gives them, with the low structural weight, very high mechanical capacities.
Concretely, the researchers 3D printed blocks that could fit together like LEGO bricks. A layer of concrete is then added to form the final beam. Beyond the reduced weight, this method allows a modular structure according to the needs and the construction project. The blocks are more easily transportable, with an installation done on site, simplifying the associated labor.
Miguel Sánchez, from the Department of Systems and Informatics of the UPV (DISCA), concludes: “Being able to customize the beams in situ makes it possible to adapt the characteristics of each of them to the structural needs at each point of construction. The possibility of recycling polymer materials to produce the beams considerably reduces their carbon footprint. “
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