Design and Fabrication of Spatially Graded Concrete Elements with Ice Aggregate Method (2022-06)¶

An important research perspective for optimization of concrete structures today can be recognized in the concept of controlled spatial grading of concrete elements. Spatial grading aims to control the volumetric distribution of concrete within an element based on the internal stresses, which enables a more efficient structural performance with less material without changing the overall geometry of a structural part. Due to high geometric complexity, the fabrication of spatially graded structures are typically based on additive manufacturing techniques such as extrusion or voxel-based 3D printing. However, for large-scale production and fabrication, 3D printing is ultimately constrained by speed and cost. This article presents the potential of regular ice as aggregate for casting spatially graded concrete components. Prefabricated ice aggregates of varying size and geometry are carefully placed into a mould to form regions with lower and higher relative densities, into which self-compacting concrete is poured. We investigate various parameters of customized ice aggregates including geometry, scale and relative densities. The presented experiments demonstrate how ice aggregate can be used to efficiently fabricate spatially graded concrete elements with high geometric complexity, while improving the structural performance by concentrating concrete only where it is needed. In addition, the intricate patterns of voids created by ice aggregate result in unique visual and lighting qualities that would be difficult to achieve with other fabrication methods. This article addresses the fundamental research questions and provides a ground for further research in digitization and automation of the ice aggregate production method.