MIT engineers have created printed glass bricks for construction

Interlocking glass bricks that can be reused and are as strong as concrete have been printed on a 3D printer they designed, MIT researchers reported on September 20, 2024.

If building materials can be assembled and disassembled as easily as LEGO bricks, then such reconfigurable masonry could be disassembled at the end of a building’s life and reassembled into a new structure, allowing generations of buildings to be built using the same building blocks.

This is the idea behind circular construction, which aims to reuse and repurpose building materials where possible to minimize the production of new materials and reduce the construction industry’s “embodied carbon,” that is, the greenhouse gas emissions associated with each building process, from production to demolition.

The idea of circular construction was brought to life by MIT engineers led by Caitlin Becker, an assistant professor of mechanical engineering, and Michael Stern, a research scientist at the Media Lab and Lincoln Laboratory, who is also the founder and director of MIT spin-off Evenline.

The team is developing a new kind of reconfigurable masonry made from recycled glass printed on a 3D printer using special 3D glass printing technology provided by Evenline.

The researchers created strong, multilayered glass bricks, each shaped like a figure eight, that interlock like LEGO bricks. The bricks were printed on a special 3D printer designed by Stern that can print with molten recycled glass.

This was the latest version of the Evenline Glass 3D Printer 3 (G3DP3). Equipped with a special furnace, the printer melts crushed glass bottles into a molten mold for printing, which the printer then applies in layered patterns.

Mechanical tests of the glass bricks showed that they can withstand pressures similar to concrete blocks. To demonstrate the feasibility of building with such bricks, the researchers built a wall of interconnected glass bricks.

The MIT specialists presented a study of the proposed technology for producing glass bricks and their physical characteristics in the article “Additive Manufacturing of Interlocking Glass Blocks,” published in the journal Glass Structures and Engineering.

In it, they note that 3D-printed glass masonry can be reused and reconfigured in the construction of both building facades and interior walls.

The team printed prototypes of glass bricks using soda-lime glass, which is commonly used in glass-blowing studios. They embedded two circular pins, similar to the pins on a LEGO brick, into each printed brick.

Like toy blocks, the pins allow the bricks to interlock and assemble into larger structures. A special material placed between the bricks prevents scratches or cracks on the glass surfaces being joined, but it is easily removed when the brick structure needs to be disassembled. It can also be recycled by melting the glass bricks in the same printer to form new shapes.

The team decided to make glass bricks in the shape of a figure eight, which allows them to be used to make walls with some curvature.

After printing samples of glass bricks, they tested their mechanical strength in an industrial hydraulic press, squeezing the bricks until they began to crack. The researchers found that the strongest bricks were able to withstand pressure comparable to that of concrete blocks.

The strong bricks were made from printed glass with a separately manufactured bonding element that was attached to the bottom of the brick. This proves that it is possible to make most brickwork from printed glass with bonding elements that can be printed or cast, or made separately from another material.

“Glass is a difficult material to work with,” Becker said. “At this stage, the most promising bonding elements were made from another material.” However, the team is studying whether it is possible to make bonding elements for bricks from printed glass.

“We have a good understanding of the limits of the material and how to scale it up,” Stern said. “We are thinking about moving into building construction and want to start with something like a pavilion — a temporary structure in which people can do something and which could then be transformed into a second structure.”

Source: IA Krasnaya Vesna