Ice Formwork for High-Performance Concrete: A Model of Lean Production for Prefabricated Concrete Industry

Abstract

This article describes an alternative material system for the fabrication of concrete precast elements using ice-based CNC-milled formwork. The use of ice as formwork resolves several systematic problems related to sustainability which are associated with the production of free-form prefabricated concrete elements, including the issue of material waste produced with existing models of fabrication. On the one hand, automation of formwork production by means of CNC machinery allows for the production of complex and precise geometries; on the other hand, as ice naturally melts away once the concrete has structurally set, the manual labor involved in the whole cycle of production is reduced dramatically. The Ice Formwork system is based on the utilization of a frost-resistant design of high-performance concrete (HPCfr). Numerous tests have proven that the Ice Formwork method of casting provides a high quality geometric transfer from ice to concrete, ensuring that no deformation of formwork occurs during the casting process. A key question is whether the trade-off in energy spent on refrigeration to maintain subfreezing temperature throughout the process of fabrication will negate Ice Formwork's validity as an alternative to traditional concrete formwork. A preliminary assessment of that question shows that the energy required to produce Ice Formwork won't outweigh the benefits of the proposed fabrication process, enabling a cost efficient and environmentally sustainable solution to casting concrete for a variety of uses.