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3D Printing Concrete on temporary surfaces: The design and fabrication of a concrete shell structure
Abstract
One of the geometrical restrictions associated with printed paste materials such as concrete, is that material must be self-supporting during printing. In this research paper a new methodology for 3D Printing Concrete onto a temporary freeform surface is presented. This is achieved by setting up a workflow for combining a Flexible Mould developed at TU Delft with a 4-degrees-of-freedom gantry printer (4 DOF) provided at TU Eindhoven. A number of hypothetical cases are studied, namely fully-printing geometries or combining 3D printing with casting concrete. The final outcome is a 5 m 2 partially-printed and partially-cast shell structure, combined with a CNC-milled mould simulating a Flexible Mould.
... Concrete printing is not good at creating cantilevering form, especially shell structures, due to the low strength property of early-stage cement. The solution for printing a shell-form object is to print it on a supporting base, and several researchers have conducted some experiments in this topic Costanzi et al., 2018). The focus of this study is not on how the support system is built but on the concrete printed shell above it, so an easily accessible method is used to obtain a base for shell printing. ...
... Unlike 2D planar layer-by-layer printing, this printing method can significantly reduce the staircase effect, which is especially noticeable for large scale additive manufacturing. A study has also proposed a 3D printed concrete on a temporary surface, the point of the method is to print closed edges and then fill them manually (Borg Costanzi et al., 2018). Freeform curvature can also be achieved using shotcrete printing, which requires jet printing operations in both vertical and horizontal directions (Placzek et al., 2021). ...
... At the same time, the method can generate several segments of print paths that are connected at the beginning and end, each segment of these print paths being within a defined area, thus allowing simultaneous printing using multiple robots without conflicts. For the discrete approach, deformable, flexible formwork (Borg Costanzi et al., 2018) and formwork made by soil accumulation can be used. ...
... Concrete printing is not good at creating cantilevering form, especially shell structures, due to the low strength property of early-stage cement. The solution for printing a shell-form object is to print it on a supporting base, and several researchers have conducted some experiments in this topic Costanzi et al., 2018). The focus of this study is not on how the support system is built but on the concrete printed shell above it, so an easily accessible method is used to obtain a base for shell printing. ...
... Unlike 2D planar layer-by-layer printing, this printing method can significantly reduce the staircase effect, which is especially noticeable for large scale additive manufacturing. A study has also proposed a 3D printed concrete on a temporary surface, the point of the method is to print closed edges and then fill them manually (Borg Costanzi et al., 2018). Freeform curvature can also be achieved using shotcrete printing, which requires jet printing operations in both vertical and horizontal directions (Placzek et al., 2021). ...
... At the same time, the method can generate several segments of print paths that are connected at the beginning and end, each segment of these print paths being within a defined area, thus allowing simultaneous printing using multiple robots without conflicts. For the discrete approach, deformable, flexible formwork (Borg Costanzi et al., 2018) and formwork made by soil accumulation can be used. ...
... Concrete printing is not good at creating cantilevering form, especially shell structures, due to the low strength property of early-stage cement. The solution for printing a shell-form object is to print it on a supporting base, and several researchers have conducted some experiments in this topic Costanzi et al., 2018). The focus of this study is not on how the support system is built but on the concrete printed shell above it, so an easily accessible method is used to obtain a base for shell printing. ...
... Unlike 2D planar layer-by-layer printing, this printing method can significantly reduce the staircase effect, which is especially noticeable for large scale additive manufacturing. A study has also proposed a 3D printed concrete on a temporary surface, the point of the method is to print closed edges and then fill them manually (Borg Costanzi et al., 2018). Freeform curvature can also be achieved using shotcrete printing, which requires jet printing operations in both vertical and horizontal directions (Placzek et al., 2021). ...
... At the same time, the method can generate several segments of print paths that are connected at the beginning and end, each segment of these print paths being within a defined area, thus allowing simultaneous printing using multiple robots without conflicts. For the discrete approach, deformable, flexible formwork (Borg Costanzi et al., 2018) and formwork made by soil accumulation can be used. ...
... In fact, medieval builders had been constructing unreinforced, compression-dominated arch and vault structures by assembling masonry blocks piece by piece [5,6]. Such structural form had attracted builders' and researchers' attention because it became a self-supported structure after assembling [5,7] and needed less or no steel reinforcement [5,[7][8][9][10]. Reduction or elimination of steel reinforcement could lower the cost during construction and maintenance phase because steel reinforcement led to increased material and installation cost and was subjected to corrosion and fire-induced deterioration in concrete [9]. ...
... However, compared to particle-bed 3D printing [31], extrusion-based 3D-printing for cement/sand-based materials currently have not only higher technology readiness but also higher economic viability for rapid fabrication for building component [32]. Therefore, the extrusion-based technology is currently a more popular technology for construction 3D-printing [32,33] and was selected by many researchers as the technologies for fabricating shell and spatial concrete structures that were compressiondominated [8,12]. ...
... To deploy such an approach for 3D-printing of dome and vault structures with dimensions enlarged to about 5 m in size, the span of robotic arm needed to be scaled up accordingly. Instead of using 6-axis robot, Borg Constanzi et al. [8] sought to use a 4-axis Cartesian robots to 3D-print an unreinforced pavilion structure. In a typical 3D-printing process where concrete extrusion nozzle was moved by a 3 or 4-axis robot in horizontal plan for depositing each layer of concrete on top of a flat print bed, the 3Dprinter stacked many consecutive concrete layers covered either same or progressively reduced areas, resulting a geometry without material overhanging. ...
Existing approaches from design to concrete 3D-printing fabrication can customize the shapes of compression-dominated concrete arches and vaults but has limited applications due to high facility requirements such as a robotic arm and a reconfigurable print bed for fabricating overhanging geometries. Therefore, there is a need to develop an alternative design-to-fabrication approach for 3D printers without such facility requirements. In this paper, concrete blocks were designed as prismatic shapes which could be customized by a most basic, gantry-based 3D printer with a flat print bed and could be assembled to a larger 3D arch structure designed based on stability and strength analyses. The feasibility of such approach was demonstrated by lab prototyping. Reduced facility requirements in this approach allow 3D-printing to be more widely applied for customizing compression-dominated structures. With further design method innovation in the future, this design-to-fabrication approach can be extended for compression-dominated structures with more complex geometries.
... The force transmission characteristics of shell structure are similar to those of arch. Borg [115] et al., designed a curved shell structure, and the connection between elements was similar to mortise and tenon joints, as shown in Fig. 21(b), which enables the panels to support themselves without the need for additional mechanical fixation. A 25 mm semi-density rubber (black in the figure) was placed between the shell elements. ...
... To date, the research and application of 3DPC technology have covered all levels of materials, structures, optimization, and connectors. [86]; (b) shell structure [115]. ...
3D printing concrete technology is an integration of material preparation, geometric modeling, structural design, and construction with the essential advantages of green, low-carbon, and intelligent construction, which had a booming development in recent years. Due to the specificity of printing materials and printing technology, 3D printing concrete exhibits unique macroscopic anisotropy, and the research on the constitutive relation of 3D printing concrete is still insufficient. Although there are numerous engineering cases of 3D printing concrete, mature structural reinforcement enhancement methods as well as quantitative structural bearing capacity analysis theories and methods are still needed to be studied. To adapt to the specific requirements of materials and printing processes, and achieve the efficient usage of materials, the optimal design is essential for 3D printing concrete structures. The field of optimal design of 3D printing concrete is currently in its infancy. Finally, the printing, connection, and construction methods of the slab, shell, beam, and arch structures provide a multi-faceted reference for 3D printing concrete structures. In general, the selection of 3D printing concrete materials and structures as well as the design and construction of structures are problematic. Based on the above-mentioned, this paper reviews four aspects which include mechanical properties of materials, structural forms, optimal design, and connection construction methods in the context of engineering examples.
... A dominant trend has focused on the decomposition and robotization of core construction tasks such as painting, bricklaying, and surveying (Warszawski 1984;Ueno et al. 1986;Skibniewski and Russell 1989;Ochoa-Franco et al. 1994;Warszawski and Navon 1998;Son et al. 2010;Saidi et al. 2016;Chen et al. 2018;Melenbrink et al. 2020). For example, mobile ground robots have been programmed to level ground surfaces, tie rebars, or inspect sites (Yang et al. 2021;Jin et al. 2021;Asadi et al. 2018), robotic arms have been enlisted to assemble timber structures, execute finishes, or install panels (Willmann et al. 2016;Kunic et al. 2021;Apolinarska et al. 2021;Lublasser et al. 2018;Park et al. 2024), and large-scale 3D printing systems have been used to pour concrete (Zhang et al. 2018;Borg Costanzi et al. 2018;Burger et al. 2022). In these, the role of workers in construction is often envisioned as managerial or Yuning Wu, Emek Erdolu have contributed equally to this work. ...
This article documents the multidisciplinary design and evaluation of a robot to assist carpentry workers on a building site in the United States. Combining ethnographic and technical design research methods, it contributes a path towards the human-centered development of construction robotics technologies. Since the 1980s, researchers have envisioned robots performing skilled construction tasks such as bricklaying, painting, spray-coating, or site monitoring. In this article, we envision instead robots performing simpler, ancillary activities supporting workers while they collaboratively carry out building tasks. We draw from an extended ethnographic engagement with construction workers to inform the design of a prototype rover able to accompany and deliver tools to carpentry workers installing formwork panels. Following a review of the state of the art in construction robotics and ethnography in technology design, we show how insights drawn from our ethnographic study informed the robot’s design as well as its innovative deep reinforcement learning (DRL) architecture for social navigation. Evaluating the robot in simulations, lab settings, and on a construction floor we document its benefits, including apt social navigation and user comfort in construction floors, and reflect on its limitations. Proposing “robot in the loop” as a design pattern combining ethnographic and technical design research, the article shows how the world of construction might be brought closer to the world of technology design, centering workers’ contexts and experiences in the design of new technologies aimed at supporting them.
... This conversion from the computer-aided design (CAD) model to machine control codes can be accomplished using slicer software [83][84][85]. Researchers have also developed algorithms employing programming tools such as MATLAB [88] or parametric design software like Grasshopper [94] to address specific research objectives. Upon receiving these codes, robot controllers interpret them and generate signals for individual manipulators. ...
To overcome productivity issues and revolutionize the stagnating construction industry, a large amount of research efforts has been devoted to robot-assisted construction technology. The advancements in robotics including mechanical system design, tool design, digital system design, and numerical control systems design enabled engineers to create complex geometries that are infeasible for conventional construction methods. In addition, innovative robotic systems that utilize mobile platforms, multiple robots, and unmanned aerial vehicles have demonstrated significant promise in fully automating the construction process. This work will provide a perspective on the state-of-the-art applications of robotics in the revolution of construction, where a comprehensive review of the current development of the relevant software and hardware, 3D concrete printing (3DCP), robot-assisted assembly of discrete prefabricated blocks, real-time quality monitoring and feedback control systems, and typical innovative robot-assisted structural designs are conducted. Finally, the limitations of existing robot-assisted construction technology are identified, which leads to several recommendations for future research toward fully automatic construction.
... Examples where such formworks are used in non-planar 3D printing include the Automated Robotic Concrete Spraying (ARCS) shell developed at the University of Cambridge [49], where several components of a vaulted ribbed floor were manufactured using a robotic shotcreting process onto a rigid curved substructure, and the Fast Complexity project [50] [55] like façade panels. More recently, these pin moulds have also been used as substrates for extrusion 3D concrete printing or shotcreting [56]. (3) Flexible formworks using textiles and meshes: Another category of formworks for concrete structures includes flexible fabric formworks, which have been investigated throughout the 20th century as a lightweight alternative to traditional formworks. ...
Digital fabrication technologies, such as 3D concrete printing, are currently making their way into the construction industry. The primary focus in this field is often on the depositing processes, such as extrusion 3D concrete printing, where material is typically applied in horizontal planar layers. This area has seen substantial progress in recent years. However, numerous research and development projects are specifically targeting the additive manufacturing of unreinforced raw concrete components. When implementing these technologies in practice, it has become clear that additional processes, such as fully automated process-parallel reinforcement integration, application of cover layers and formative and subtractive post-processing of the components, are essential for successful application. In addition, by varying the orientation, characteristics and arrangement of the layers, new shapes and functions can be realised. Examples include angled layer orientation for producing vaulted geometries without support structures, as well as non-planar layer formation for complex component geometries or assembly joints. Moreover, alternative innovative manufacturing processes, such as KnitCrete, Smart Dynamic Casting or Injection 3D Printing, reveal new potential for the application of digital manufacturing technologies in the construction industry. This article aims to demonstrate the possibilities offered by digital fabrication with concrete beyond the stacking of horizontal planar layers, and how these technologies can complement and expand a future digital fabrication strategy in the construction industry. 1. The versatile opportunities of digital fabrication with concrete-a systematic approach The construction industry recently witnessed a paradigm shift with the emergence of (concrete) 3D printing technology. For the construction sector, 3D printing is an ideal digital fabrication technology as it combines the advantages of automation and customisation. 3D printing promises unprecedented possibilities in the realm of ecological, sustainable , and efficient building practices. It stands out as a trans-formative technology with the potential to minimise the carbon footprint by optimising material usage [1] while being both fast and productive [2] when precisely depositing strands with robots. However, most works focus exclusively on printing horizontal planar concrete strands. Alternative innovative 3D printing processes, or possible combinations of conventional 3D printing with other digital manufacturing processes are not given enough attention. Therefore, this article aims to highlight and integrate various digital processes that extend beyond horizontal planar layers. We focus on holistic approaches that consider the material, the process, and the design in an integrated manner for digital concrete fabrication. Thus, in addition to 3D Concrete Printing techniques, we discuss digitally controlled concrete casting, surface trowelling, and milling technologies. By examining these processes together, we seek to promote more sustainable construction practices through advanced digital methods.
... Moreover, these methods generate waste in the form of discarded formwork. To address this, various efforts have been directed towards developing reconfigurable and reusable 3DCP surfaces that can be utilized for H-3DCP [4][5][6]. ...
... Characteristic of this approach is researchers' analysis of construction tasks into smaller chunks amenable to automation, placing fewer people "in the loop" in less labor-intensive, and often supervisory roles. For example, drones are proposed for bricklaying, spray-coating, or building masonry structures [14][15][16], mobile ground robots are programmed to level ground surfaces, tie rebars, or inspect sites [17][18][19], robotic arms are enlisted to assemble complex timber structures, execute finishes, or install panels [20][21][22][23][24], and large-scale 3D printing systems are used for pouring concrete [25][26][27]. ...
Construction is one of the world’s largest and least automated industries, relying on the cooperation of multiple people with diverse skillsets in labor intensive, physical tasks. Since the 1980s, efforts to introduce robots into construction contexts have mostly focused on automating discrete tasks or monitoring site activities. In this paper, by contrast, we show how robots might be designed to adaptively support the cooperative work of construction teams. Following an indicative review of the state of the art in construction robotics, the paper shows how a detailed ethnographic study of construction workers shaped the design, development, and evaluation of a robot able to assist a team of carpentry workers by delivering tools and hardware during the installation of formwork panels. The resulting prototype is a building companion rover guided by state-of-the-art deep reinforcement learning (DRL) methods and an innovative social navigation stack. Through quantitative and qualitative evaluations in lab settings and on a construction site, we show how the rover can adaptively support carpentry workers taking their specific workflow into account. By documenting these technical and conceptual contributions, we hope to bring ”robotically-supported construction” into focus as a domain of interest for the construction robotics community.
... As collapse was found to be caused either by plastic material failure or elastic buckling failure, this property was found to depend on both the initial strength and stiffness of the mortar upon deposition and the structuration rate, i.e., the rate of development of these properties during the printing time [94]. These properties also largely define the geometrical possibilities specifically regarding objects that feature cantilevering parts [95]. -Open time, the time interval during which a next layer can be applied without an excessive loss of interface strength relative to the bulk material strength [69,96,79,97]. ...
3D Concrete Printing (3DCP) is presented as an important process in the future of civil engineering, as it accelerates the construction process, reduces labor costs, and potentially generates significantly less waste materials. Currently, 3DCP has been delayed as a technical solution for Latin American. However, it could be an important option for tackling the housing deficit in developing countries as well. The deployment of 3DCP depends on many different local factors, either political, economic, or technological. This paper discusses the potential, challenges, and research needs to deploy 3DCP in Brazil. It starts presenting the Brazilian economic context in the struggle to reduce the housing deficit over the years. Then, the challenges related to the implementation of 3DCP are compared with the opportunities, such as the abundance of low-carbon materials (earth-based, biomass, etc.), which could turn 3DCP into a sustainable business. Although this review is focused on Brazil, the authors believe that the context also applies to many other developing countries with similar social inequality conditions.
... 3D concrete printing (3DCP) is an innovative technology that offers numerous advantages, including low labor costs, low carbon dioxide emissions, time efficiency, user convenience, and design flexibility [1,2]. The implementation of 3DCP also provides notable environmental benefits, such as reduced manufacturing waste, a decreased carbon footprint, and support for the principles of a circular economy [3][4][5][6]. However, the current approach to 3DCP relies heavily on trial and error methods, leading to increased costs and longer development times for the final product [7][8][9]. ...
... For example, a bathroom unit fabricated using 3DCP achieved 25.4% reduced cost, 48.1% enhanced productivity, and 85.9% reduced carbon emission compared to the precast one [6]. The formwork-free construction of 3DCP enables arbitrary design of structures with complex geometries, e.g., hollow structures [8,9], curved shell structure [10], artistic columns [11], etc. However, the major hurdle to the wide application of 3DCP is lacking of a compatible method for introducing steel reinforcement [12]. ...
3D concrete printing (3DCP) is a form-free construction method that offers the potential to construct load-efficient structures with unique shapes. However, 3DCP currently lacks a compatible reinforcement method. This paper aims to print self-reinforced lightweight slabs using engineered cementitious composites (ECC). By introducing honeycomb-like (HS) and rectangular hollow sections (RS) into printed ECC slabs, the self-weight of HS and RS slabs is reduced by over 30.5% and 35.7%, respectively, compared to that of a solid slab. The flexural behaviors of the printed slabs were investigated via four-point bending test and finite element modeling. Experimental results show that the printed ECC slabs exhibit typical ductile failure even in the absence of steel reinforcement. The maximum flexural strength-to-mass ratio of HS and RS slabs approaches 0.049 MPa/kg, which almost equals to the value of solid slab. The numerical models were validated using the experimental results. Furthermore, parametric analysis reveals that bond strength higher than 1.5 MPa can achieve a stable flexural behavior for HS slab. The findings lay the groundwork for load-efficient and lightweight structural design by using ECC in 3DCP.
... Viele Einsatzgebiete ergeben sich bei der AF von Beton. Doppelt-gekrümmte Schalen aus gedrucktem Beton stellenCostanzi et al. [2018] vor. Stand Mai 2023 entsteht in Heidelberg das größte aus Beton gedruckte Gebäude Europas.1 ...
ENGLISH ABSTRACT: In this thesis it is investigated how common connection-elements in steel-construction can be manufactured by means of Wire Arc Additive Manufacturing (WAAM). The idea was to replace the manual and time-consuming assembly process, which is still common today, by a fully-automated manufacturing-step through additively manufacturing the connection elements directly onto the steel beams.
The basics and particularities of WAAM are explained and described. To enable WAAM-compatible design, theorems as science-based statements are formulated. With the 8-step optimization process presented in this work, the structures of the connection-elements are determined. This ensures that the material is statically optimally utilized while a fast and error-free manufacturing process is guaranteed. Numerical topology-optimization and numerical ultimate-load analysis are used in the optimization process.
For practical demonstration, three connection elements (beam hook, load-introduction stiffener, clamping element) are optimized. In a following chapter, suitable manufacturing strategies for these connection elements are outlined. The manufacturing process with the WAAM is described. The ultimate load-capacity of the connection elements is determined via destructive tests. In an evaluation chapter, the outcomes of these tests are compared with the numerical ultimate load-capacities.
GERMAN ABSTRACT: In dieser Arbeit wird untersucht, wie stahlbauübliche Anschlusselemente mittels Wire Arc Additive Manufacturing (WAAM) gefertigt werden können. Die Motivation liegt darin, die heutzutage weiterhin übliche händische und zeitaufwendige Baugruppenfertigung durch einen voll-automatisierten Produktionsschritt zu ersetzen, indem die Anschlusselemente direkt auf Stahlträger additiv gefertigt werden. Die Grundlagen und Besonderheiten des WAAM werden dafür erläutert und beschrieben. Zur Ermöglichung eines WAAM-gerechten Konstruierens werden Lehrsätze im Sinne einer wissenschaftlichen Aussage formuliert. Mit dem präsentierten 8-schrittigen Optimierungs¬prozess werden die Strukturen der Anschlusselemente ermittelt, sodass das Material statisch optimal ausgenutzt wird und gleichzeitig eine schnelle und fehlerfreie Fertigung gelingt. Im Optimierungsprozess werden die numerische Topologieoptimerung sowie die numerische Trag¬lastanalyse genutzt. Drei Anschlusselemente (Trägerhaken, Lasteinleitungssteife, Spann¬element) werden bespielhaft optimiert. Im darauffolgenden Kapitel werden für jene Anschluss¬elemente geeignete Fertigungsstrategien erarbeitet und die Fertigung mit dem WAAM beschrieben. Die Tragfähigkeit der Anschlusselemente wird in zerstörenden Versuchen ermittelt und abschließend in einem Auswertungskapitel mit den numerischen Tragfähigkeiten verglichen.
... Concrete printing is not good at creating cantilevering form, especially shell structures, due to the low strength property of early-stage cement. The solution for printing a shell-form object is to print it on a supporting base, and several researchers have conducted some experiments in this topic (Lim et al., 2020;Costanzi et al., 2018). The focus of this study is not on how the support system is built but on the concrete printed shell above it, so an easily accessible method is used to obtain a base for shell printing. ...
... 3DCP allows the printing nozzle to automatically extrude concrete materials layer-atop-layer and build structures with reduced manual work with a given building model. The formwork-free process enables 3DCP to construct structures with complicated geometric configurations that are difficult to achieve using conventional construction methods [3,4]. ...
... Large scale additive manufacturing of cement-based materials has been hailed as a novel construction technology in the last few years which changes the traditional building practices via a computercontrolled positioning process to manufacture freeform constructions [1][2][3]. The printing is done mainly by extruding fresh cement paste layer-by-layer through a fine nozzle which is controlled by a computer in compliance with a 3D model [4][5][6]. ...
... 3DCP allows the printing nozzle to automatically extrude concrete materials layer-atop-layer and build structures with reduced manual work with a given building model. The formwork-free process enables 3DCP to construct structures with complicated geometric configurations that are difficult to achieve using conventional construction methods [3,4]. ...
Global greenhouse gas emissions from the construction concrete industry are 50% higher than those from all other industries
combined. Concrete incorporating waste and recycled materials could help lessen the negative efects of environmental
problems. Agricultural waste is increasingly being used to substitute cement in environmentally friendly concrete produc�tion. Rice husk ash (RHA) is a workable alternative that merits further investigation. Since evaluating the properties of
concrete containing RHA requires extensive and time-consuming experimentation, machine learning (ML) can accurately
predict its properties. Consequently, this study aims to anticipate and develop an empirical formula for RHA concrete’s
compressive strength (CS) using ML algorithms. This study employs several ML methods such as random forest, support
vector machine, light gradient boosting machine (LightGBM), extreme gradient boosting (XGBoost), and SHAP. A total
of 192 data points are used in this study to assess the CS of RHA-blended concrete. The input parameters are age, amount
of cement, rice husk ash, superplasticizer, water, and aggregates. Across all ML models, the XGBoost method is used to
build a highly accurate predictive model. Predicting RHA concrete's CS using an existing XGBoost model is consistently
accurate. R2
demonstrates a CS of 0.99 during training and 0.94 during testing. Model characteristics and complex correla�tions are explained using the SHAP algorithm. The proposed model’s prediction outcomes are compared to prior research,
and the best ML algorithm is selected.
... Three-dimensional printing concrete technology, also known as additive manufacturing of concrete, is a rapid prototyping technology based on 3D architectural models [1,2]. Due to the advantages of low labor cost, fast construction speed, no formwork and suitability for various construction sites, 3D printing concrete technology has been widely used [3,4]. ...
The effects of different mineral admixtures on the evolution of static yield stress of common composite cementitious material paste and ultra-high-performance concrete (UHPC)-based paste were investigated. The results show that there are obvious differences in the role of mineral admixtures in the common paste and the UHPC-based paste. Adding mineral admixtures can change the initial static yield stress of the paste by affecting the particle size, particle shape and the charged particles. The addition of mineral admixtures with small particle size such as silica fume and ultrafine slag can increase the initial static yield stress of common paste but reduce that of UHPC-based paste. Adding mineral admixtures changes the evolution of static yield stress of the paste by affecting the particle spacing and the formation and growth rate of hydration products. In turn, the addition of ultrafine slag or silica fume increases the growth of the static yield stress of common paste. Adding slag, fly ash or fly ash microbeads successively reduces the static yield stress of common paste at the later stage. Affected by the content of PCE, the static yield stress of UHPC-based paste containing fly ash microbeads, slag, ultrafine slag and fly ash increases sequentially compared with the blank group at the later stage. The effect of silica fume with different dosages on the evolution of static yield stress of UHPC-based paste is significantly different.
... Seyedahmadian et al. [13] extruded reinforced polymer composites onto the template in a specific direction to meet the requirements of the structure in 2015. Costanzi et al. [14] presented a new method to print concrete on the temporary freeform surface in 2018. However, the mechanical performance of 3D printed components is found to be susceptible to the removal of the temporary formwork and, as temporary templates usually cannot be reused, the problem of material and cost waste has not been well-solved. ...
The development and application of new Fiber Reinforced Polymer (FRP) material and 3D printing construction technology provide a basis for making up for the shortcomings of traditional thin-shell structures and building new thin-shell structures with better performance. In this paper, a new 3D Printing Composite (3DPC) thin-shell structure is proposed, which is prepared using a FRP plate as a permanent base mold and combining it with 3D printing cement technology. Both the typical experiment and finite element numerical simulation analysis of the 3DPC thin-shell structure are carried out. The results show that the maximum load capacity of the 3DPC thin-shell structure is increased by 53.3% as compared with the corresponding traditional concrete thin-shell structure. The presence of the FRP sheet effectively delays the generation of initial cracks and enhances the ductility of components.
... Figure 11. Examples of toolpath generated from different strategies: (a) direction-parallel path [89], (a,ii) in 3DCP process, the orientation of reference line of a direction-parallel toolpath can be altered between layers to create complex inter architecture [90], (b) contour-parallel path [89], (c) hybrid toolpath that combines both strategies [91], (d,i and d,ii) toolpath created with spacefilling pattern Peano curve and Hilbert curve [92]. ...
3D concrete printing (3DCP) offers solutions for affordable construction including cost minimisation, productivity improvement, and sustainability alignment, as well as being able to tailor products with complex design requirements. Various 3DCP techniques, printable materials, and computational design tools have been developed to meet the requirements of mechanical and structural properties as well as durability. Coupled with parametric design and numerical simulation approach, the 3DCP could enable further construction optimisation, and realisation of complex designs. While major effort is devoted to developing materials and mix designs, limited attention is given to the development of predictive modelling and design optimisation specifically for 3D printing of concrete/mortar from the fresh to the hardening states. The benefit of additive manufacturing in construction is often recognised by the building of highly complex structures obtained from the generative design or structural optimisation processes. Here, various constraints need to be considered, such as overhang angle, printing direction, anisotropic properties of concrete, and printing toolpath optimisation. Continuous improvement in non-deterministic/statistical or machine learning (ML) approach could also lead to the development of a future robust 3DCP simulation tool when data is scarce or limited. This work will provide a snapshot of the current state-of-the-art development of modelling and design optimisation tools for 3D concrete printing.
... Nematollahi et al. in [12] report some remarkable benefits of using extrusion-based additive manufacturing methods in respect of reducing the construction cost and time, 20 reducing the injury rates and increasing architectural freedom. Several types of construction 3D printers such as Cartesian robots [13], robotic arms (manipulators) [14], cable driven parallel robots [15] and Delta robots [16] are currently in use and various objects [10] have been produced by these robotic platforms. ...
In this paper, to have control over geometry specifications of rectangular bar-shaped layers in a robotic concrete 3D printing process, a real-time vision-based control framework is developed and proposed. The proposed control system is able to set the layer-width by automatically adjusting the velocity of an industrial manipulator during the 3D printing process of concrete based materials relying on a vision system feedback. Initially, details related to the control system, vision and processing units, and robotic platform are discussed. In continue, technical descriptions related to the printhead design, conversion process from a digital 3D drawing model to numerical motion control commands of an industrial manipulator and building material used in this work are reported. The reliability and responsiveness of the developed system is then evaluated through experimental tests by printing several single bar-shaped layers with different wideness by means of an unique printhead geometry and also by printing two layers with the same dimension centrally above another. Overall, the high accuracy and responsiveness of the developed system demonstrate a great potential for real-time vision-based control of industrial manipulators for layer-width setting in concrete 3D printing applications.
... Although the process offered adequate accuracy, it resulted in a relatively long printing time [7]. Borg Costanzi et al. [16] were printing only the outer layer of the module and then filling the infill with fresh concrete, which significantly reduced the production time. The last group of approaches was done fully automated, however, the methods of reinforcing the modules have not been demonstrated. ...
Although they are very efficient structures, concrete shells have lost popularity due to the complexity of the traditional construction process using cast-in-place concrete. A key concept to overcome the labor-intensive formwork in situ is the segmentation of the shells into prefabricated parts. In order to avoid individual formworks during prefabrication as well, the authors rely on extrusion-based 3D printing of strain-hardening cement-based composite (SHCC). The goal is a highly automated, scalable, and adaptable flow-prefabrication of modules controlled by a holistic digital design process. Such the creation of modular free-form shell structures can be accelerated significantly, resulting in structures comparable with gridshells. Starting with the problem statement and the elaboration of the technology used, the main contribution of this research is the development of geometrical methods for modularization based on given production conditions. The challenge lies in the free-form geometry discretization with respect to the structural analysis and within the defined constraints such as planar quads, no edge torsion, and minimal material consumption. Methods of discrete differential geometry for circular PQ (planar quad) mesh generation are combined with Response Surface Methodology (RSM) for multi-objective optimization of the global parameterized shape. The results were illustrated in a study case where the geometrical and structural production parameters of starting and final shell are compared.
3D Printing (3DP) technology, one of the layered production methodologies where design and construction configurations can be made with increasing digitalization and Industry 4.0, is one of the leading techniques of the period. 3D Concrete Printing (3DCP) also comes to the fore in the construction industry. The study aims to observe the impact of architectural design decisions on the 3DCP process by developing controlled and consistent design alternatives. Architectural designs developed with different geometric forms in the housing function were subjected to digital planning, 3DCP preparation, and 3DCP prototype final product stages. In the integration of design and 3D concrete printing (3DCP), two key aspects were investigated: (i) the impact of different geometric forms (square, rectangle, hexagon, octagon, circle, and ellipse) on the buildability performance of 3D-printed structures, and (ii) how variations in design details influence printing time, material consumption, cost, and the feasibility of mass production in architectural applications. For the 3DCP process, 3D-printable cementitious mixture was developed, and a 3D printer with dimensions of 100 x 100 × 40 cm was used. The results obtained during the printing process were analyzed in comparison with the building evaluation parameters. As a result, the house with circular geometry showed the optimum behavior according to the parameters of buildability, cost, and mass producibility. The circle geometric form provides a 4.2 % advantage over the octagon in terms of buildability, a 16.6 % advantage over the ellipse in terms of cost, and a 20 % advantage over the ellipse in terms of mass producibility.
The use of concrete, which has an essential place in the construction sector, is becoming increasingly widespread in the sector with the additive manufacturing method. On the other hand, three-dimensional concrete printing (3DCP) technology, the centre of attention of many researchers, is still a developing method in the sector. Analyses on the current status of 3DCP are considered important in guiding academic studies on the potential and future of the subject. In this context, the study aims to evaluate the current status and potential of 3DCP technology in the AEC (architecture, engineering and construction) industry. In this study, the bibliometric analysis method was used to identify, select, evaluate and systematise the research literature on three-dimensional concrete printing technology in building production for the purpose of the study and to create new perspectives for future studies. According to the criteria determined within the scope of the study, 241 articles were reached in the Web of Science database. VOSviewer and biblioshiny programmes were used to determine data such as annual number of publications, publication production of countries, number of citations, and keywords. According to the findings based on the content of the reviewed articles, research on 3DCP technology is mainly focused on the fields of construction, performance and design. In this context, 35% of the 60 most cited papers were focused on construction, 57% on performance and 8% on design. According to the study's output, further research and application are needed in the field of 'design'. In this study, it is seen that 3DCP technology is still an emerging field and there is a need for further research and application in terms of 'design' in terms of the AEC sector. In this context, it is thought that the study will provide important references in terms of processes and trends in the sector.
Dünne Betonschalen ermöglichen eine erhebliche Materialeinsparung. Die herkömmlichen Herstellungsmethoden von Betonschalen, die auf der Betonage in einer Schalung basieren, sind jedoch aus heutiger Sicht unwirtschaftlich. Der modulare Ansatz kann den Schalenbau deutlich kosteneffizienter machen, insbesondere, wenn Module mit einem hohen Automatisierungsgrad gefertigt werden. Das laufende Projekt „Schalungsfreie Fließfertigung adaptiver Tragstrukturen aus variablen Rahmenelementen – ACDC and beyond“ zielt darauf ab, einen Ansatz für die vollautomatische Herstellung von Betonschalenmodulen mit variabler Geometrie zu entwickeln. Besonderes Augenmerk gilt dabei der Bewehrung der Module, die mittels automatisierter Verlegung von Carbongarnen erfolgt. Die Konturen der Module werden mit hochduktilem Beton (engl.: Strain‐Hardening Cementitious Composite, SHCC) 3D‐gedruckt. Dieser Aufsatz stellt die im Rahmen des Projekts erzielten Ergebnisse vor und gibt einen Überblick über die laufenden Arbeiten, zu denen die Herstellung nicht planarer Module, die Einführung von Nachbearbeitungstechniken und die Verbesserung der Nachhaltigkeit der Technologie gehören.
Three-dimensional printable concrete (3DPC) has become increasingly popular in the building and architecture industries due to its low cost and fast design. Currently, there is great interest in the mix design methods and mechanical properties of 3DPC, particularly in relation to yield stress analysis. The ability to extrude and build 3D-printed objects can be significantly affected by factors such as the rate of extrusion, nozzle size, and type of pumps used. It has been observed that a yield stress lower than 1.5 to 2.5 kPa is not sufficient to maintain the shape stability of concrete, while a yield stress above this range can limit the material’s extrudability. Furthermore, the strength properties of 3DPC are influenced by factors such as changes in yield stress and superplasticiser dosages. To meet the high mechanical strength and durability requirements of 3DPC in the construction industry, it is essential to analyse the material’s early-age mechanical properties. However, the development of standardised test methods for 3DPC is still deficient. To address this issue, a bibliometric analysis was conducted to comprehensively review the diverse test methods and mechanical characteristics of 3DPC with different mix proportions. To produce high-performance concrete from various additives and waste materials, it is critical to have a basic understanding of the hydration processes of 3DPC. Moreover, a detailed analysis of the environmental impact and energy efficiency of 3DPC is necessary for its widespread implementation. This review article will highlight the recent trends, upcoming challenges, and benefits of using 3DPC. It serves as a taxonomy to navigate the field of 3DPC towards sustainable development.
Inspired by the diving bell of the water spider, this paper designs and fabricates nature-inspired 3D printed strain-hardening cementitious composites (3DP-SHCC) reticulated shell roofs. The compression performance and energy absorption capabilities of 24 specimens with eight different strut angles are evaluated through a combined experimental and simulation approach. The results demonstrate that all specimens exhibit excellent ductility and structural integrity under ultimate load conditions. The 45–45 and 60–60 specimens exhibit the highest energy absorption and efficiency, respectively, while 60–90 specimens exhibit the best ductility. Compared with traditional lightweight concrete structures, reticulated shells have lower average structural density, higher specific energy absorption, and ductility index values. A building with a proposed nature-inspired 3DP-SHCC reticulated shell roof is constructed to verify buildability, demonstrating reduced construction time and enhanced automation. This paper offers valuable insights for highly automated construction projects, especially in extreme environments.
Purpose
The purpose of this study is to identify and assess new risks in construction projects that use 3D printing.
Design/methodology/approach
A mixed approach of both qualitative and quantitative methods was used. Literature review was conducted to extract 30 risks of 3D printing in construction. A survey was then developed to assess the probability and impact of these risks. In total, 37 respondents, who have experience and/or knowledge of 3D printing, completed the survey. The risk priority was calculated using a fuzzy logic approach. The main benefit of the proposed model is being able to use numerical and linguistic data in the risk assessment model.
Findings
The results show that the main risks, in terms of priority, are lack of codes and regulations for 3D printing in construction, delay in government approvals, shortage in labour skilled in 3D printed construction, lack of knowledge and information of 3D printed design concepts and changes in 3D construction codes and regulations.
Originality/value
This paper fills an identified gap in the literature related to 3D printing in construction and provides insights into the key risks affecting this disruptive technology.
As a formwork-free construction method, 3D-printed concrete (3DPC) shows great advantages in forming complex structures; but encounters buildability problems. To address this, this paper presents a fluid-solid integrated peridy-namic (PD) model to describe the fluid-to-solid transition of 3DPC. On this basis, an automatic strategy is proposed to deal with complex geometries. Programming by Python, PD particles are automatically generated by the input geometric model and arranged in a layer-wise manner for 3D printing simulation. The particles are then connected into inter-and intra-layer bonds to model the weak interface between layers. This establishes a connection between digital fabrication and PD simulation and offers a general way for 3DPC buildability analysis, which is assessed by the modeling of a 3D printing test and two digitally designed structures. The satisfactory results prove that the proposed method is applicable to structures with different geometries, thus enhancing the advantages of 3D printing.
3D printing technology revolutionizes construction by creating custom building components with increased efficiency
and reduced waste. This paper reviews advancements in the 3D printing of cementitious materials,
focusing on integrating mineral additives (MAs) like metakaolin, micro-silica, slag, and fly ash to address
environmental and economic challenges linked with high-Portland cement content in 3D concrete printing
(3DCP). MAs enhance the pumpability, printability, and buildability of 3DCP while reducing its environmental
impact. The review emphasizes optimizing cement mixtures, including alkali-activated materials, to enhance
sustainability and performance. It discusses the mixture design’s importance, balancing mechanical properties
and environmental impacts, and examines MAs’ influence on rheological properties, mechanical performance,
and 3DCP durability, including layer bond strength. The paper also discusses global 3D printing technology
adoption in construction and challenges in additive manufacturing implementation. By analyzing printing parameters,
mixture proportions, and materials’ effects on long-term performance, this review highlights 3D
printing’s potential for economically viable and eco-friendly structural elements. It aims to guide future advancements
in 3D printable cementitious materials, meeting modern construction demands while addressing
traditional concrete production’s environmental challenges.
Establishing a safe and sustainable lunar base on the moon is the foundation for human exploration and development activities. Due to the high transportation costs of the Earth Moon space, a large amount of construction materials are difficult to obtain from Earth. Therefore, how to utilize lunar resources for in-situ construction on the lunar surface has become the key challenge for the construction and operation of lunar base. Faced with special lunar simulant materials and extreme lunar environments, lunar construction faces a series of problems and challenges. This article conducted research on lunar regolith simulant and forming process, providing guidance for lunar surface construction.
Extrudability and constructability are two important, yet contradictory issues pertaining to the construction of three-dimensional (3D) printing concrete. Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion, but the printed structure is easily collapsible. However, a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable. This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design. First, a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties. Next, a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out. The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable. Furthermore, an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.
3D concrete printing (3DCP) is an innovative construction technique that enables the creation of complex and customized structures. This technology offers advantages such as reduced waste materials, faster construction times, and the ability to produce unique designs with intricate details. This article reviews the latest advancements in the 3DCP technology, its potential to transform the building and construction industry, and the latest developments in the 3DCP systems, methodologies, materials, and applications. The article concludes that several parameters and concrete mix proportions heavily influence the 3DCP process. Using waste materials as supplementary cementitious materials can significantly improve the 3D-printed concrete’s rheology, but the excessive use can decrease the early strength. Lastly, using recycled sand in 3D printing can reduce the flexural stiffness and strength of the printed objects when loaded from different directions. The article also categorizes large-scale 3DCP technologies, highlighting the need to optimize printing ink for better economic and environmental outcomes using waste materials in 3DCP applications.
In this experimental research project we report on the manufacturing process of the first full-size 3D printed concrete structure in our country. The house was 3D printed by an ABB IRB 6700 robot whose range we made fit with the requirements for transportation size and also, its range determined the size and geometry of the house. During the transformation process from sketch to code we involved students to apply computational design methods. We designed the main load bearing structure which had to be thinnest and lightest possible together with its insulation features and printability. We were aware of the world-wide research in this field started by NASA centennial Challenge called 3D-printed-habitat [Roman,2020] as well as start-ups derived from this research [1,2,3,4]. During the project, we investigated the following matters: (1) the relationship between geometry of the wall in model and in practice (2), setting of the robot and the mixture; and (3) stress test of the wall. With the results of the test we aimed at contribution to standardisation of 3D printed structures in ISO/ASTM 52939:2021. The finalized structure, named "Prvok", was made to prove printability of the mixture and stability of the design.
Digital construction has become known in recent years as "Industry 4.0" and promises a revolution in the construction industry with the potential of free architecture, less waste of materials, reduced costs and increased worker safety. Digital fabrication techniques and cementitious materials have intersected significantly in recent years. Despite the potential for revolution in the construction industry, with predictable benefits such as greater structural efficiency, reduced material consumption and waste, etc., unlike traditional production methods, it will also have new challenges and demands. In this article, first, a review of the relevant literature on 3D printing in construction, its challenges were discussed. They were then identified and categorized from the perspective of business analysis from a literary perspective for investment. This article presents a critical review of the relevant literature on 3D printing in construction. Challenges are grouped into eleven groups according to the requirements of business analysis. The main challenges found through the literature are related to materials. The most frequently mentioned challenges are the ability to print materials, the ability to build and capture. In addition, scalability, structural integrity, and lack of regulations are often cited as major challenges. This article fills a gap in the literature as it addresses a new aspect of 3D printing from a business perspective that is a risky investment.
While significant efforts have been devoted to material and printing process optimisation for 3D concrete printing (3DCP) on flat surfaces, printing on non-planar or complex surfaces remains challenging. In this work, a design-to-printing framework that combines digital models and physical printing processes is developed and validated for 3DCP on non-planar and curved surfaces. Parametric studies are conducted to investigate the correlations between printing parameters, surfaces' slopes, and filaments' geometries. This paper demonstrates that while the printing instability is mainly attributed to inaccurate deposition of filaments accumulated throughout the process, controlling nozzle height is the key for successful printing on non-planar surfaces. Moreover, printings on surfaces inclined at less than 20° comply with the strength-based stability criteria. Printing parameters, such as nozzle height, printing speed and extrusion volume can be tuned to create suitable toolpath and associated GCode for stable printing on complex surfaces.
Doubly-curved ribbed concrete shells are a materially efficient means of spanning large areas such as roofs and floors. However, the fabrication of such structures poses challenges in terms of formwork manufacturing as well as material deposition. This has led to their decline compared to more prismatic shapes such as flat slabs which can be manufactured more economically. This paper presents a novel fabrication process called Automated Robotic Concrete Spraying (ARCS) by which glass fibre reinforced concrete (GFRC) is sprayed onto a curved formwork to create thin shell components of variable thickness. The trajectory planning and generation algorithm developed and implemented in ARCS to create such components is presented. Two sets of prototype shells were fabricated: one which forms the segments of a larger structural floor demonstrator and another consisting of a single component with deep ribs on a thin shell. The sequencing used to generate the spray paths for each component is outlined, with each prototype using two different strategies to add ribs onto the fabricated shells. While the fabrication process has been used in conjunction with a pin-bed mould actuating flexible formwork to create the spraying surface, the trajectory planning approach is adaptable enough such that any formwork can be utilised. Combined with the output speed of material deposition, ARCS offers the potential to enable mass production and customisation of doubly-curved ribbed structural concrete shells of variable thickness as an industrial process at an architectural scale.
Quantitative damage identification of surrounding rock is important to assess the current condition and residual strength of underground tunnels. In this work, an underground tunnel model with marble-like cementitious materials was first fabricated using the three-dimensional (3D) printing technique and then loaded to simulate its failure mode in the laboratory. Lead zirconate titanate piezoelectric (PZT) transducers were embedded in the surrounding rock around the tunnel in the process of 3D printing. A 3D monitoring network was formed to locate damage areas and evaluate damage extent during loading. Results show that as the load increased, main cracks firstly appeared above the tunnel roof and below the floor, and then they coalesced into the tunnel boundary. Finally, the tunnel model was broken into several parts. The resonant frequency and the peak of the conductance signature firstly shifted rightwards with loading due to the sealing of microcracks, and then shifted backwards after new cracks appeared. An overall increase in the root-mean-square deviation (RMSD) calculated from conductance signatures of all the PZT transducers was observed as the load (damage) increased. Damage-dependent equivalent stiffness parameters (ESPs) were calculated from the real and imaginary signatures of each PZT at different damage states. Satisfactory agreement between equivalent and experimental ESP values was achieved. Also, the relationship between the change of the ESP and the residual strength was obtained. The method paves the way for damage identification and residual strength estimation of other 3D printed structures in civil engineering.
The copper alloy shell is an important component, and its forming methods include hot forging, spinning, and multi-pass cold extrusion. The purpose of this paper is to study a new process of bimetallic 3D printing technology in the integrated manufacturing of copper alloy shells. In this paper, the 3D printing technology and bimetal 3D printing technology are briefly described first, and then the experimental analysis of 3D printing technology is carried out, and then the three-dimensional model of the copper alloy water meter is established. Through analysis and comparison, the experimental results show that with the increase of sintering temperature, the density of copper alloy samples gradually increases. Because the copper powder particles are more closely combined with the increase of the sintering temperature, the relative density of the sample becomes larger and larger. The integrated copper alloy shell through 3D printing technology remanufacturing technology can change the density, thermal conductivity, dynamic viscosity coefficient and solid phase rate of the integrated copper alloy shell under the condition of setting a certain temperature. Higher plasticity and thermal conductivity. The copper alloy shell integrated by bimetal 3D printing remanufacturing technology can improve the application range of alloy materials.
The proliferation of digital technologies considerably changed the field of architecture. Digital fabrication pushes architecture into an unexpected new domain of previously unachievable complexity, detail, and materiality. Understanding these technologies’ impact can help direct future research, innovate design and construction processes, and improve the education of future professionals. However, comprehensive reviews offering a holistic perspective on the effects of 3D printing technologies on architecture are limited. Therefore, this study aims to provide a systematic review of state-of-the-art research on 3D printing technologies in architectural design and construction. The review was performed using three major databases, and selected peer-reviewed journal articles published in the last ten-year period were included in quantitative and qualitative analyses. Using bibliometric analysis, the research progress is summarized through the identified trend of the annual number of articles, prominent authors and co-authorship network, and key topics in the literature organized in three clusters. Further, content analysis of selected articles enabled coding cluster themes. Moreover, the analysis differentiated two categories of 3D printing technologies based on the scale of the system, elaborating their peculiarities in terms of materials, methods, and applications. Finally, challenges and promising directions for future work and research challenges are discussed.
Keywords: architecture; design; digital fabrication; construction industry; additive construction; additive manufacturing; rapid prototyping; 3D printing; models; prototypes
In the field of digital fabrication, additive manufacturing (AM, sometimes called 3D printing) has enabled the fabrication of increasingly complex geometries, though the potential of this technology to convey both geometry and structural performance remains unmet. Typical AM processes produce anisotropic products with strength behavior that varies according to filament orientation, thereby limiting its applications in both structural prototypes and end-use parts and products. The paper presents a new integrated software and hardware process that reconsiders the traditional AM technique of fused deposition modelling (FDM) by adding material explicitly along the three-dimensional principal stress trajectories, or stress lines, of 2.5-D structural surfaces. As curves that indicate paths of desired material continuity within a structure, stress lines encode the optimal topology of a structure for a given set of design boundary conditions. The use of a 6-axis industrial robot arm and a heated extruder, designed specifically for this research, provides an alternative to traditional layered manufacturing by allowing for oriented material deposition. The presented research opens new possibilities for structurally performative fabrication. Copyright © 2016 by Kam-Ming Mark Tam, Caitlin T. Mueller, James R. Coleman, and Nicholas W. Fine. Published by the International Association for Shell and Spatial Structures (IASS) with permission.
Process-based biomimetics focuses on the transfer of biological principles to architectural construction. To realise the ICD/ITKE Research Pavilion 2014 -15, presented here by Moritz Doerstelmann, Jan Knippers, Valentin Koslowski, Achim Menges, Marshall Prado, Gundula Schieber and Lauren Vasey of the Institute for Computational Design (ICD) and Institute of Building Structures and Structural Design (ITKE) research team at the University of Stuttgart, sensor-driven robotic fabrication was combined with advanced design computation and simulation. This enabled the construction of an architectural fibre structure on a pneumatic mould, drawing on the complex design of the web of a water spider.
The production of precast, concrete elements with complex, double-curved geometry is expensive. This is caused by the high cost of the necessary moulds and the limited possibilities for reuse. Currently, computer numerically controlled milled foam moulds are the solution applied in various projects. These moulds deliver good aesthetic performance, but also result in a waste of material, relatively low production speed and fairly high costs per element. The flexible mould method, as discussed in this thesis, offers an economic alternative for the state of art: it allows repeated reuse of the same mould in an adapted shape.
Additive manufacturing is gaining ground in the construction industry. The potential to improve on current construction methods is significant. One of such methods being explored currently, both in academia and in construction practice, is the additive manufacturing of concrete (AMoC). Albeit a steadily growing number of researchers and private enterprises active in this field, AMoC is still in its infancy. Different variants in this family of manufacturing methods are being developed and improved continuously. Fundamental scientific understanding of the relations between design, material, process, and product is being explored. The collective body of work in that area is still very limited. After sketching the potential of AMoC for construction, this paper introduces the variants of AMoC under development around the globe and goes on to describe one of these in detail, the 3D Concrete Printing (3DCP) facility of the Eindhoven University of Technology. It is compared to other AMoC methods as well as to 3D printing in general. Subsequently, the paper will address the characteristics of 3DCP product geometry and structure, and discuss issues on parameter relations and experimental research. Finally, it will present the primary obstacles that stand between the potential of 3DCP and large-scale application in practice, and discuss the expected evolution of AMoC in general.
In this paper, a non-conventional way of additive manufacturing, curved-layered printing, has been applied to large-scale construction process. Despite the number of research works on Curved Layered Fused Deposition Modelling (CLFDM) over the last decade, few practical applications have been reported. An alternative method adopting the CLFDM principle, that generates a curved-layered printing path, was developed using a single scripting environment called Grasshopper – a plugin of Rhinoceros®. The method was evaluated with the 3D Concrete Printing process developed at Loughborough University. The evaluation of the method including the results of simulation and printing revealed three principal benefits compared with existing flat-layered printing paths, which are particularly beneficial to large-scale AM techniques: (i) better surface quality, (ii) shorter printing time and (iii) higher surface strengths.
Viscometers in general have never been particularly popular at the jobsite. They are however well suited at the laboratory as they measure concrete consistency in terms of fundamental physical quantity, known as the yield stress and plastic viscosity. In contrast to viscometers, the slump cone is by far the most accepted tool for measuring consistency at the jobsite. This is due to its simplicity in handling. With the significance of both types of devices, it is clearly important to relate them to each other. The result of this study suggests a relationship between the yield stress and slump that depends on the concrete mixture proportions. More precisely, a particular trend line between the yield stress and slump seems to depend on volume fraction of matrix used in the concrete. The study shows a low correlation between the slump and plastic viscosity.
Developing a computational approach towards a performance based design and robotic fabrication of fibrous skin structures
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