Advances in the science of making concrete have led to a new class of cement composites called ultra-high performance concrete, or UHPC.

The durability of UHPC makes it an ideal material for use in solutions as critical as highway infrastructure repair and replacement. While it has been around for nearly 15 years, it's only now finding acceptance among architects. The high compressive and tensile strength of UHCP allows architects to undertake the redesign and optimization of various structural elements in their work.

UHPC is being tested for use in precast concrete piles, seismic retrofitting of aging bridges, as an overlay on crumbling bridge decks and even as protective structures to hold back explosive detonations. If you live in the U.S. or Canada, you might already have driven across a bridge using UHPC components.

Now architect Philippe Morel, of Studio EZCT Architecture & Design Research in Paris, has used 3D printed sand molds and UHPC to create novel structures from the ultra high-strength concrete.

The German 3D printer company voxeljet printed Morel 130 sand mold halves to use in creating his concrete casting art.  Morel says the material, a steel fiber-reinforced cement composite material some six to eight times stronger than conventional concrete – and also much lighter than traditional concrete mixtures – might be the key to a new generation of 3D printed structures of astonishing beauty, strength  and durability.

"We needed a quick and cost-effective process for manufacturing molds for UHPC casting," Morel said. "The only economic alternative for our research is to print sand molds (on the voxeljet machines) using 3D printing technology."

Morel's UHPC exhibit is being shown at an architectural trade fair in the FRAC Centre in the city of Orléans.

He says that after his structures are printed, both the inside and outside of the molds were coated with epoxy resin and then glued together, and he says he thinks it might soon be possible to 3D print structures using ultra-high performance concrete as material directly.