The company, called SpaceCrete, was set up by civil engineer and serial inventor Michael Butler and although his system is not yet commercially available it is covered by US patents with EU patents pending.
Despite still being in the early stages of development, SpaceCrete even won ‘Most Innovative Construction Product’ at the 2023 World of Concrete show in Las Vegas in January.
“We work at the interface between machine control and finished concrete structure,” said Butler. “We developed the admixture and delivery system that allows vertically-shaping fluid concrete, rather than traditional forming.
“The vertical shape can be defined by simple or sophisticated construction hardware or new technology – such as 3D printing – but using essentially normal concrete.”
The SpaceCrete system uses inline mixing to modify the pumped concrete with a special admixture called 3D-Admix. According to Butler only 0.25% of 3D-Admix is required to transform normal concrete into SpaceCrete.
“A five-inch [127mm] slump becomes zero slump inline – but with extreme shear thinning – so you can still pump it and work it as needed,” says Butler.
He explained that extreme shear thinning means that vibrating SpaceCrete consolidates it thoroughly, locking it into place and enabling it to build up vertically.
As SpaceCrete allows pumped concrete to be ‘stacked’ vertically without forming, it opens up many new ways to build with the material.
“Your normal delivered concrete can become 3D print material with a very low dose of 3D-Admix injected into the pump line. Or you can slip-form vertically very rapidly with pumpable concrete.
“The form pressure is gone the moment you stop vibrating it,” said Butler.
Using a vertical screed rail, you can define a finished vertical plane of concrete as fast as you can pump it, Butler claims. “This allows you to place solid concrete walls over rough excavations, insulating foam panels, or any vertical surface,” he said.
SpaceCrete “really is a new concept, and sceptical contractors are very impressed,” said Butler, adding that his invention is “way greener and cheaper than 3D-print mortars; but our method development is rapid-light slip forming, not 3D-printing”.
Butler added that SpaceCrete meets all existing US codes and is “a healthy replacement for noxious shotcrete”.
Butler is now looking for commercial partners to help perfect SpaceCrete and make it commercially available.
“We are solely a method and material R&D developer on a very low budget,” he said. “We would like to share our knowhow, trade secrets and IP [intellectual property] with an established construction-related business, preferably one having significant manufacturing and/or marketing infrastructure in place.”
SpaceCrete is currently making samples of 3D-Admix available in small quantities. For more information, click here.
You can watch video of early trials here.