February 2, 2021 at 2:56:44 PM
First Carapace Mold Complete
The University of Southern California team at Clark Pacific lifted the completed first panel from the CARAPACE PAVILION mold on January 25. Four more panels to go! This was the smallest and easiest one. No rebar. Less than 3 inches thick at the narrowest point. Double-curved geometry. This is the foundation panel (and it is upside down as it come out of the mold). The team reset the mold on January 28 to get ready for the second cast.
The USC School of Architecture CARAPACE PAVILION uses an "Ultra-High-Performance-Concrete" (UHPC) called "Ductal" by LafargeHolcim. It is very, very strong.
Professor Doug Noble writes:
Regular concrete has a typical compressive strength of about 4000psi to 6000psi. Our engineering friends at Walter P Moore used a design value of 17,000psi for our special UHPC project. When you use precast concrete, you take samples of each batch and test them later to make sure that they met or exceeded the design values. Using the machine in the photo, the Clark Pacific technician compresses the samples until they fail. Normally, this is done on one sample after 7 days and another sample after 28 days. Concrete gets harder every day.
Our 7th-day compression test just came in at 22,215psi.