Integrating Wire Arc Additive Manufacturing into Selective Paste-Intrusion for Reinforced Concrete Elements (2023-12)¶

This research aims to integrate the Wire Arc Additive Manufacturing (WAAM) process into the Selective Paste Intrusion (SPI) process to enable the production of reinforced concrete elements with complex geometries. However, the high temperatures generated during the steel melting process in WAAM can locally lead to a full stop of hydration which consequently is linked to a decrease of the mechanical properties of the concrete in the bonding zone around the reinforcing bar. This study aims to determine the maximum allowable temperature at which concrete retains sufficient hardening conditions which allows strength development when combining SPI with WAAM. In practical application, this temperature limit can directly be affected by e.g. the protruding length of the WAAM-reinforcing bar above the SPI particle bed or external cooling strategies. As continuation of previous research, this study establishes a link between actual and targeted temperatures in the steel bar to allow the combination of WAAM and SPI processes. Temperature limits without compromising mechanical performance are investigated, and the need for and extent of additional cooling measures are evaluated. The results show that temperatures of the concrete in the fresh state can reach up to 70°C without weakening its mechanical performance.