Flow-Based Pultrusion of Anisotropic Concrete: Mechanical Properties at Hardened State

The issue of reinforcement for 3D concrete printing has received considerable attention, as constructions have to comply with reliability principles and building standards. Here a specific process called Flow-Based Pultrusion for additive manufacturing (FBP), inspired by pultruded composite manufacturing and built on existing extrusion-based 3D printing technology, permits to impregnate numerous continuous fiber rovings pulled by the extrusion flow of a fine mortar [4]. The resulting extruded material, an Anisotropic Concrete, is isotropic transverse like unidirectional long fibers composite. The mechanical properties are greatly influenced by the quantity of fibres (reinforcement ratio) and their impregnation quality [2]. These factors are related to the process parameters [3], the mortar rheology for impregnation and the fibre dosage (roving thickness, roving count) for reinforcement ratio. Full-scale experiments are presented, using fibre rovings to increase the reinforcement ratio up to 3%, which is comparable to the steel/concrete ratios in traditional rebar-reinforced concrete elements. The influence of reinforcement ratio on the tensile strength and ductility of the hardened material is presented.