Could buildings one day be made from materials that are as easy to take apart as LEGO bricks? A team of engineers at MIT believes so, and they are developing a new kind of reconfigurable masonry made from 3D-printed, recycled glass.

While it may sound nuts to use glass as a building material, structural tests show the strength of the glass bricks to be comparable to their concrete counterparts. This fresh approach to building materials could transform how we build and dismantle structures. One day it could help to make the industry more sustainable and reduce its carbon footprint.

A Circular Approach to Construction

The 3-D printed glass bricks were inspired by “circular construction,” a growing movement in architecture that seeks to reuse materials across multiple building lifetimes. By reducing the need to manufacture new materials, the hope is to cut down the greenhouse gases linked to construction, known as “embodied carbon.” These emissions accumulate throughout a building’s life — from material production to eventual demolition.

Motivated by this vision, MIT engineers have created durable, multilayered glass bricks using 3D-printing technology. Each brick, shaped like a figure-eight, is designed to interlock—much like LEGO bricks. The team envisions future buildings that can be taken apart, with their bricks reassembled into new structures or recycled into entirely different shapes.

“Glass is a highly recyclable material,” says Kaitlyn Becker, an assistant professor of mechanical engineering at MIT. “At the end of a structure’s life, these glass bricks can be disassembled and reassembled into something new, or even remelted and printed into another form.”

Breaking New Ground with Glass

Glass may seem like an unlikely choice for a building block. Generally, it’s seen as fragile and unsuitable for major structural elements. However, this project, led by Becker and Michael Stern, an MIT graduate and founder of Evenline, a company specializing in 3D glass printing, will make you challenge this assumption.

“Glass as a structural material kind of breaks people’s brains a little bit,” says Stern. “But we’re showing this is an opportunity to push the limits of what’s been done in architecture.”

The team recently tested their glass bricks under mechanical stress, finding that the strongest bricks could withstand pressures comparable to those borne by concrete blocks. That’s a significant milestone for glass as a building material, showing that it can offer both recyclability and strength.

Stepping Toward More Sustainable Architecture

The inception story of this research first began at MIT’s Glass Lab, where Becker and Stern first encountered the material during their undergraduate studies. Soon, their fascination with glass’s recyclability and optical properties set them on a path to explore how it could work for construction.

Stern eventually devised a 3D glass printer. The latest iteration of the printer, G3DP3, melts recycled glass bottles and turns them into a printable form. Next, the glass is layered into sturdy bricks, each with interlocking pegs like those in LEGO blocks.

In addition to their mechanical strength, the bricks offer flexibility in design. The figure-eight shape allows them to be stacked into walls that can curve and shift, allowing for more dynamic architectural structures.

So, the researchers see vast potential for this technology. In the near future, they hope to build pavilions and temporary structures that can be reassembled into new forms. The long-term vision is to grant these glass bricks “many lives”. They can be reused in different projects, reducing the need for new materials and cutting down on waste.

While more research is needed to refine the interlocking features, which are currently made from materials other than glass, the team remains optimistic about scaling up their design.

“We have more understanding of what the material’s limits are, and how to scale,” says Stern.

For now, the team is focused on constructing progressively larger glass structures, from small walls to potentially entire buildings.

The findings were reported in the journal Glass Structures and Engineering.