Researchers develop lego-style 3D printed alternative to reinforced concrete beams
A team of researchers from Polytechnic University of Valencia (UPV) has developed a 3D printed alternative to reinforced concrete beams made from recycled plastic.
Although extremely strong, reinforced concrete beams are also very heavy because they contain a lot of metal. As a result, moving such beams is often difficult and requires a substantial amount of energy.
To solve these problems, researchers have designed and patented 3D printed plastic beams that can be assembled like lego bricks and concreted in place, weighing up to 80% less than traditionally reinforced concrete or metal beams.
“Our goal was to offer an alternative to current reinforced concrete structures,” said José Ramón Albiol, professor at the Higher Technical School of Building Engineering (ETSIE) at the UPV. “These consist of profiles built over the entire length of the part, which requires expensive installations and is difficult to transport.”
3D printed beams inspired by human bone
The UPV team embarked on 3D printing of plastic blocks that could be split together to form beams, as an alternative to traditional reinforced concrete or metal beams. In order to achieve significant weight savings compared to such beams, the researchers modeled their 3D printed blocks on the internal polymer profile structures of human bones.
The alveolar structure, typical of that found in the epiphysis – or terminal part – of bones, consists of a partially spongy layer with a trabecular porous framework and a thick, compact outer layer. The researchers replicated this geometric structure in their 3D printed blocks to give them strength and rigidity while keeping the parts as light as possible.
The blocks were also printed using recycled plastic as a raw material to improve the sustainability of the building process.
“It is a honeycomb structure, which makes it possible to reduce the plastic material used – and therefore its weight – while maintaining structural rigidity”, specifies Albiol. “And that’s what we transferred to these revolutionary beams, especially to profiles. It is a very intelligent natural system and its replication in these beams gives them, with a low structural weight, a very high mechanical capacity.
A lego building blocks approach
The UPV team has developed their 3D printed beams over the past three years and patented the system in October 2020.
In addition to the weight saving benefits of printing plastic beam components, the main novelty of the researchers’ system is its modularity, whereby the 3D printed blocks can be assembled on site to form a longitudinal beam. which is then set up. in place with a layer of concrete.
As a result, large trucks and cranes are not required to transport and install the beams, saving time and cost of labor and materials.
“The system also eliminates the need for expensive formwork, allowing you to work without having to reduce traffic in the infrastructure in which you are working,” said José Luis Bonet of the University Institute of Concrete Sciences and Technologies (ICITECH) of the UPV. . “Additionally, this solution reduces the manpower and ancillary resources required, resulting in significant cost and time savings.”
Additionally, the use of 3D printing means that entire beams can be both fabricated and assembled on site regardless of location, and beams can be customized to suit individual project needs as needed.
“Being able to customize the beams in-situ makes it possible to adapt the characteristics of each of them to the structural needs of each point of application”, added Miguel Sánchez of the Department of Computer Systems and Computers (DISCA) of the UPV. “The ability to recycle polymeric materials for the manufacture of beams also significantly reduces its carbon footprint.”
Progress in concrete 3D printing
The strengths of 3D printing have been increasingly harnessed in recent years in the construction industry to provide improved material characteristics, reduce manufacturing times and costs, and reduce the industry’s carbon footprint.
In October of last year, researchers from UC Berkeley has developed a new method of incorporating 3D printed polymer byte lattices into concrete structures as reinforcement. They were able to reduce the concrete content of the mixture by about 33%, making the overall weight of the structure much lighter while still retaining its bearing capacity.
Elsewhere, researchers from ETH Zurich used a combination of FDM 3D printing and large-scale molding methods to design a concrete “eggshell” 3D printing process. The method allows the team to produce complex concrete structures in a more material efficient manner.
More recently, scientists from Swinburne University of Technology and Hebei University of Technology is committed to improving sustainability in the sector by reusing construction waste in 3D printable concrete.
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Featured images show the 3D printed plastic beam alternative to reinforced concrete. Photo via UPV.