Aerial additive building manufacturing of 3D printed cementitious structures

Abstract

This paper describes and evaluates a cementitious paste solution for the first aerial additive building manufacturing system, developed to create and repair civil engineering structures in-situ using materials 3D extrusion-printed by aerial robots. Cementitious pastes without aggregate were created to determine their suitability for a powered deposition device light enough to be carried by an aerial robot. Mixes of varying water/cement ratio and plasticiser content, along with admixtures, were manufactured and the curing of the pastes was monitored using a cone penetrometer. Flexural test specimens were manufactured using the deposition device and moulded compressive test specimens were created by hand. Strengths in excess of 40 MPa (compressive) and 2.74 MPa (flexural) were achieved. The optimal mix for extrudability had a water/cement ratio of 0.33 with 1.5% superplasticiser by weight of cement added. This mix remained workable for an hour without additional chemical retardation. The autonomous deposition device successfully imported and extruded workable cementitious paste, demonstrating the structural and operational feasibility of cementitious pastes for autonomous 3D extrusion-printing using aerial robots.