Topology-Optimization-Based Additive Construction for Sustainability

For decades, concrete structures have been constructed using cementitious materials through conventional methods using formworks (either cast-in-place or precast). Concrete with a sufficient slump is needed to fill up the formwork. This approach results in significant material wastage (where the material is placed in regions with low to very low stresses) and increases the carbon footprint of structures. Additive construction offers unique opportunities to build form-free structural elements with complex geometry which enable topology and structural optimization. Topology optimization is a method of optimizing geometries using algorithmic models to optimize material layout within a user-defined space for a given set of loads, conditions, and constraints. Topology optimization maximizes the performance and efficiency of the design by removing redundant material from areas that do not need to carry significant loads to reduce weight or solve design challenges like reducing resonance or thermal stress. Topology optimization looks to magnify the performance of the design while also minimizing the amount of material used. This paper includes 1) the development of 3D-printed versions of concrete with lower embodied carbon; 2) additive construction of compression-only (C-only) structures; and 3) experimental testing of small-scale C-only structures.