3D Concrete Printing: A Systematic Review of Rheology, Mix Designs, Mechanical, Microstructural, and Durability Characteristics

Abstract

This paper provides a state-of-the-art report on the up-to-date research on the emerging 3D concrete printing technology from the concrete materials perspective. It reviews the recent research focused on understanding and characterizing the rheological necessities of the concrete printing process and discusses how the researchers are tailoring compatible mix proportions for the 3D concrete printing process by using eco-friendly binders, waste aggregates, chemical admixtures, and nano-additives. This paper systematically evaluates anisotropic behavior in the mechanical properties of printed concrete and establishes an order for anisotropic behavior in the compressive, flexural, and tensile strengths along three different axes (X, Y, and Z axes) of printed concrete. It evaluates the ratio of flexural strength to the compressive strength of printed concrete along the above three axes. This article explains the influence of variation of printing process parameters on the mechanical properties and discusses reinforcement approaches used for increasing structural performance. The microstructure at the interface of adjacent layers and also at the interface of the reinforcement-cement matrix is discussed. The recent research on the durability performance of printed concrete is critically discussed and future research needs for 3D concrete printing are identified in this paper.

A critical review of 3D printing and digital manufacturing in construction engineering

“…Additionally, it increases mechanical strength with the addition of active additives such as micro-silica, fly ash and shell rock flour (Inozemtcev et al , 2018). Some important additives, such as eco-friendly binders (silica fume, metakaolin and fly ashes), nanoparticles (nano-silica, nano-attapulgite clay) and chemical additives, are very useful for tuning the rheology of concrete, which controls the materials flow in a nozzle (Rehman and Kim, 2021).…”

Comparison of Properties of 3D-Printed Mortar in Air vs. Underwater

“…Various concrete structures have been constructed using 3DCP technology [ 11 ]. A two-story municipality building in Dubai by Apis Cor [ 12 ], a community village in Austin by ICON [ 13 ], vehicle-hiding concrete arches in California by the U.S. Marines Corps [ 14 ], a prestressed bicycle bridge in Eindhoven [ 15 ], and optimized reinforced concrete beams in Ghent and Naples [ 16 , 17 ] were constructed by the 3DCP technology.…”

Additive Manufacturing in Off-Site Construction: Review and Future Directions

“…Although multiple types of extrusion techniques can be employed during concrete printing, most approaches can be analyzed in terms of building material transportation, printhead mechanisms, subsequent material deformation during deposition, and material properties promptly after deposition [ 43 ]. The effects of gravity-induced flow, viscoplastic flow inside the system, tensile forces along the nozzle opening, and compression forces during deposition are assessed during the design stage by testing the characteristic requirements of the material, such as pumpability, extrudability, shape retention, printing open time, and buildability [ 32 , 41 , 43 , 44 ].…”

“…Adjusting the mixture proportion or choosing an entirely new composition is proposed if the proposed benchmark cannot be achieved. Afterwards, the shape stability should then be evaluated based on successive tests such as the cylinder stability test and the layer settlement experiment [ 44 , 94 , 95 ]. The cylinder stability tests investigate the influence of different materials on the geometrical stability of the product, while the layer settlement experiment evaluates the stability of successive printed layers.…”

“…The shear viscosity of the material can typically be used as an indicator of material pumpability [ 96 ]. Multiple studies that relate pumpability and material rheology have been performed, but standard test specifications are still lacking [ 44 ]. On the other hand, buildability pertains to the dimensional consistency of the material during deposition despite experiencing constant stress when layers are repeatedly printed on top of each other [ 32 ].…”