Sand molds for ultra-high performance concrete

Additive manufacturing constantly opens up new application fields in architecture. Now architect Philippe Morel from Studio EZCT Architecture & Design Research in Paris is using printed sand molds for research with ultra high-strength concrete.

The acronym UHPC (ultra-high performance concrete) has become symbolic of somewhat of a revolution in architecture. It refers to fiber-reinforced concrete types that are six to eight times stronger than conventional concrete, and also much lighter. The significantly denser structure of UHPC also provides excellent material quality without pores and micro tears.   

The research activities of the EZCT focus on the search for lighter and filigree concrete structures that will provide a completely new level of design freedom in architecture in the future. "We needed a quicker and more cost-effective process for manufacturing molds for UHPC casting. At this time, the only economic alternative for our research work is to print sand molds on the fast voxeljet machines using 3D printing," says Philippe Morel.

Using the example of the spectacular UHPC exhibit, which can still be seen at an architecture trade fair in the FRAC Centre in Orléans until the end of March 2014, voxeljet printed a total of 130 sand mold halves for the concrete cast. After printing, the inside and outside of the various halves were infiltrated with epoxy resin and were subsequently glued together in order to achieve a very fine concrete structure. This process was followed by casting using ultra-high performance concrete, and the assembly of the individual parts. 

Philippe Morel only partially removed the sand molds from the part to demonstrate how the complex UHPC structure was created. Philippe Morel believes that the direct 3D printing of parts made of ultra-high performance concrete and bypassing the use of sand molds will be the only alternative to this production method in the future. To turn this vision into reality, voxeljet's development departments have already been studying the 3D printing of concrete materials for some time.