3D-printed thermoset formworks for casting complex concrete structures: Displacement analysis

This study investigates the mechanical behavior of 3D-printed thermoset materials and their application in complex concrete columns formwork, aiming to provide an adaptable and cost-effective construction solution. While thermoplastic polymers have been used in formwork applications, they face issues such as delamination, warping, deformation under hydrostatic pressure, and difficult demolding. To overcome these challenges, this research introduces two-component thermoset materials, which have not been previously employed in formwork applications. The objective is to assess the material properties of the 3D-printed thermosets and evaluate the resulting formwork's performance. The analyzed formwork shapes are designed for aesthetics, structural efficiency, and material optimization, reducing waste by transitioning from simple to innovative and unique complex shapes. Material performance is evaluated by measuring the modulus of elasticity and Poisson's ratio, focusing on layer orientation relative to the load direction. Results show that 3D-printed thermosets exhibit strong interlayer bonding and effectively isotropic material properties. After the formwork is 3D-printed, it is filled with self-compacting concrete and displacement over time is monitored using Digital Image Correlation. Experimental results are compared to numerical simulations of the formwork, showing good agreement in both displacement fields and magnitude. Long-term monitoring (24 hours) shows near-constant displacement in all formworks, effectively managing thermal expansion and contraction, even when detached from the concrete. Importantly, the thermoset formwork is demolded without damage, allowing for potential reuse. Overall, these findings suggest that 3D-printed thermosets offer a promising solution for efficient, adaptable formwork in complex concrete applications.