2021 Peter Rice Prize: Erin Hunt and Yaxuan Liu’s “NuBlock”

macro image of porous material

by Erin Hunt (MDes Tech ’21) and Yaxuan Liu (MArch I ’21) — Recipient of the Peter Rice Prize

NuBlock brings a modern and aesthetic update to an architectural and structural elementary unit, the brick. With its innovative water-soluble formwork, this project can create lighter concrete bricks through a gradient of variable porosities with intricate geometries and infinite customizability. In areas where greater structural stiffness is required, the block is denser and vice versa. The goal is to minimize the quantity of material necessary through formal optimization while maintaining structural performance and decreasing the embodied carbon latent in concrete fabrication.

Polyvinyl alcohol (PVA) is a biodegradable, water-soluble polymer that is conventionally used as a secondary support material in 3D printing. For this project, PVA is used as a primary print material for 3D printing concrete formwork. It allows for the creation of concrete components with hollow parts and undercuts, as well as other scenarios in which removing or breaking the formwork would be labor intensive, if not impossible. Typically, casting complex forms in concrete requires large and multipart formwork, but in this project a single PVA mold is used for casting and then dissolved with water, leaving the intricate block behind.

Rendering showing the NuBlock dome in a forest.

A new modular fabrication method was developed for NuBlock to overcome the limit of a 3D printer’s bed size, reduce the risk of print failure, and eliminate the material bridging and need for support structures. Multiple parts of a formwork are held together with wooden dowels. This allowed for the block’s volume to increase since the entire block was not being printed at once. An additional usable formwork was designed and printed in polylactic acid (PLA) filament to complement the PVA formwork.