Evaluating manual and robotic placement of reusable modular formwork for digitally integrated concrete manufacturing

The construction industry is under increasing pressure to reduce the environmental impact of concrete while maintaining efficient production. Structural optimisation offers a method for reducing material usage but typically results in non-standard geometries and internal voids that are not economically viable to produce using conventional formwork approaches. In precast concrete production, such features are often not systematically integrated into the manufacturing process, as existing solutions rely on disposable materials or labour-intensive manual procedures. This study investigates a modular, reusable formwork system for the generation of small voids in concrete elements, designed for robotic placement. A robotic pick-and-place process was implemented within a digitally supported production environment, and experimental trials were conducted to compare robotic placement, manual placement, and conventional EPS-based practice. Across all investigated placement scenarios, the mean module displacement amounted to 0.354 mm with a standard deviation of 0.806 mm, while no systematic differences in geometric performance were observed between manual and robotic placement. Subsequent process stages, particularly concrete compaction, contributed the highest to the observed geometric deviations. Manual placement times varied with operator experience and showed higher variability. Simulation results show that removing operator-mediated interruptions and adjusting motion parameters reduced robotic cycle times by 82.5 % under idealised conditions, reaching a level comparable to experienced manual operators in the laboratory experiments. The findings demonstrate the feasibility of robotic and manual placement of reusable modular formwork and provide a quantitative basis for the further development of digitally supported precast concrete manufacturing processes.