Injection 3D Concrete Printing (I3DCP): Basic Principles and Case Studies

Abstract

Today, the majority of research in 3D concrete printing focuses on one of the three methods: firstly, material extrusion; secondly, particle-bed binding; and thirdly, material jetting. Common to all these technologies is that the material is applied in horizontal layers. In this paper, a novel 3D concrete printing technology is presented which challenges this principle: the so-called Injection 3D Concrete Printing (I3DCP) technology is based on the concept that a fluid material (M1) is robotically injected into a material (M2) with specific rheological properties, causing material M1 to maintain a stable position within material M2. Different to the layered deposition of horizontal strands, intricate concrete structures can be created through printing spatially free trajectories, that are unconstrained by gravitational forces during printing. In this paper, three versions of this method were investigated, described, and evaluated for their potential in construction: A) injecting a fine grain concrete into a non-hardening suspension; B) injecting a non-hardening suspension into a fine grain concrete; and C) injecting a fine grain concrete with specific properties into a fine grain concrete with different properties. In an interdisciplinary research approach, various material combinations were developed and validated through physical experiments. For each of the three versions, first architectural applications were developed and functional prototypes were fabricated. These initial results confirmed both the technological and economic feasibility of the I3DCP process, and demonstrate the potential to further expand the scope of this novel technology.Materials 2020, 13, 1093 2 of 17 approaches of additive manufacturing in construction (AMC) are mainly based on the following methods: particle bed printing [2] and material extrusion [3]. A third emerging technology, the so-called Shotcrete 3D Printing, is based on material jetting [4].Particle bed printing is a process where fine particles are selectively bound through the localized application of binder. For this, a thin layer of particles is evenly distributed inside a given building envelope. In a subsequent step a binder is deposited onto the particle layer, which selectively bonds the particles. Next, the particle bed is lowered, a new layer of particles is applied, and the binding process is repeated. In a layered manner, complex geometries can be fabricated, resting loosely inside the bed of unbound particles. This technology is used, for example, for the production of complex molds in metal foundry [5], but also in architecture as formwork for casting high resolution concrete parts [6]. Instead of using the printed element merely as formwork, there are also attempts to entirely print structural elements using large, room-sized particle bed printers [7].In the extrusion-based approach to additive manufacturing, strands of fine concrete are printed layer-wise on top of each other, progressively creating a three-dimensional object. Here, predominantly two differen...

Large Particle 3D Concrete Printing—A Green and Viable Solution

“…Further innovative techniques are currently being investigated but are still at the early stage of development, for example, Injection 3D Concrete Printing, which is overcoming the layer-by-layer build-up of the component [ 19 , 22 ].…”

Foundation Piles—A New Feature for Concrete 3D Printers

“… ( a ) Flexible Mould [ 5 ], ( b ) Entry Control Point [ 11 ], ( c ) material injected into a gel [ 28 ], ( d ) use of a gripper for lintel placement [ 27 ]. …”

“…ApisCor presented the concept of printing a flat slab by laying concrete trails at the appropriate angle [ 25 ]. The articles [ 28 , 32 ] present a method, called Injection 3D Concrete Printing, which is based on the concept that a liquid building material is injected into a gel-type support material with specific rheological properties ( Figure 1 c). This ensures that the support material maintains the stable position of the construction material.…”

“…A completely different approach to mix design must be taken when printing in a support material [ 28 , 32 ], where it is important to protect the mix from the adsorption of its components by the absorbent support material by using viscosity modifying admixtures. Printing when using support materials based on the Particle Bed Fusion technique [ 59 , 60 , 61 ] involves injecting a binder into a specially prepared substrate.…”

“…In the literature, we can find examples where the printer also plays the role of a crane transporting prefabricated elements during construction (Figure 1d) [26,27]. [11], (c) material injected into a gel [28], (d) use of a gripper for lintel placement [27].…”