Presented by Marchant van den Heever, Stellenbosch University
Extrusion-based 3D concrete printing (3DCP) prompts a new age of reinforced concrete structures by virtue of the exponential advancements in process, control, material, and fresh-state analysis technologies. However, owing to the anisotropic mechanical behavior exhibited by 3DCP elements, the successful integration of existing reinforcement systems is paramount to permit the omnipresent adoption of 3DCP. Recent literature presents suitable strategies for reinforcement implementation, which considers the compatibility of various techniques to both fabrication process and object geometry. In this research, the compatibility and performance of a coupled reinforcing strategy, comprising of entrained high-modulus polypropylene (HM-PP) micro-fibers and conventional steel rebar, is reviewed. Identical beams with biaxially symmetric cellular infill patterns are loaded in four-point flexure and eccentric three-point flexural configurations, to ascertain the pure flexure and shear-flexure performance of the dually and singularly (only HM-PP fibers) reinforced elements. The attained load-displacement response curves indicate that the ultimate load-carrying capacity and ductility of the dually reinforced configuration outperforms the singularly reinforced configuration. Additionally, the comparability of the proposed reinforcing strategy is verified for the gantry style fabrication process employed. Supplementary finite element simulations further validate these insights.
