We’ve all heard the buzz about 3D-printed concrete homes and how they can speed up construction. But there’s a catch that often gets overlooked. Even when a house is printed quickly, the concrete still needs up to 28 days to cure properly. That means nearly a month of waiting before the structure reaches full strength. A new printable material, however, might change that timeline dramatically by curing in just three days.
Why Traditional Concrete Takes So Long
Concrete may seem simple, but it’s made of three key ingredients: water, an aggregate like sand or gravel, and cement. The cement is the glue that holds everything together, and it’s also the part that takes the longest to cure.
But curing time isn’t cement’s only issue. Producing traditional Portland cement is extremely energy intensive. Manufacturers grind limestone and other raw materials, then heat them to temperatures as high as 1,450 ºC. The heating process releases huge amounts of carbon dioxide. Even more CO2 escapes when the limestone itself breaks down through calcination. When you combine both sources, cement production accounts for an estimated 5 to 8 percent of all human-made greenhouse gas emissions.
A Greener, Faster Alternative
This is where an innovative new 3D-printable material steps in. Developed by Assistant Professor Devin Roach, doctoral student Nicolas Gonsalves, and their team at Oregon State University, the mixture is made mostly from clay soil. To enhance it further, they add hemp fibers, sand, and biochar. Biochar is a charcoal-like substance created when organic materials like wood chips are heated without oxygen in a process called pyrolysis.
Instead of relying on carbon-heavy Portland cement, this blend uses an acrylamide-based binding agent that reacts to heat. When the material exits the 3D printer’s nozzle, a process called frontal polymerization begins immediately, kick-starting the curing process right on the spot. This gives the freshly printed material enough strength to span openings such as windows without collapsing.
Strength That Builds Fast
Roach explains that their printed material reaches a buildable strength of 3 megapascals the moment it’s laid down. That means walls can be stacked layer by layer, and unsupported features like roof overhangs can take shape right away. Even more impressive, the mixture surpasses the 17 megapascals required for residential concrete in just three days, compared to the nearly month-long wait for traditional cement.
The benefits don’t stop there. Although it becomes strong enough to build on within days, it fully cures in eight to ten days, eventually reaching strengths above 40 megapascals.
What’s Next for This Material
The team is now focusing on making the material more affordable. At the moment, it’s still more expensive than standard concrete mixes. But with further development, it might offer builders a faster, greener way to create durable structures without the heavy environmental cost of cement.
This breakthrough hints at a future where 3D printing could revolutionize sustainable construction even more than we imagined.
Source: Oregon State University
