On-demand additive manufacturing of functionally graded concrete

ABSTRACT The rapid development of additive manufacturing of cementitious materials has enabled the emergence of a new design paradigm, namely functional grading of material properties by location. Target performance parameters could be material weight and insulation value or (particularly important) ductility. A generic concept to achieve this, is through the selective addition of fibres or aggregates. In 3D concrete printing (3DCP), this concept can be developed into two strategies: by adding particles (i) to the bulk mixture through a second stage mixing process at the printer head (Simultaneous Process, SP), or (ii) in between the layers of deposited cementitious filament (Repetitive Sequential Process, RSP). The present paper presents the development of specific equipment required to obtain on–demand functional grading of the printed material. Subsequently, the application of these systems in print trials is shown. The current study focussed on ductility by creating fibre–reinforced 3D printed concrete through both strategies. The mechanical performance of the obtained material has been established through compressive, flexural, and crack–mouth opening displacement tests. To underline the generic nature of the strategies, a trial with lightweight aggregates has also been performed. It was shown that particularly the SP is capable of achieving improvements in ductility and self–weight.

[1]  Richard J. Malak,et al.  Computational Design of Gradient Paths in Additively Manufactured Functionally Graded Materials , 2018, Journal of Mechanical Design.

[2]  Fabio Gramazio,et al.  Complex concrete structures: Merging existing casting techniques with digital fabrication , 2015, Comput. Aided Des..

[3]  M. B. Bever,et al.  Gradients in polymeric materials , 1972 .

[4]  Albert J. Shih,et al.  Three-Dimensional Printing Multifunctional Engineered Cementitious Composites (ECC) for Structural Elements , 2018, RILEM Bookseries.

[5]  Neri Oxman,et al.  Functionally Graded Rapid Prototyping , 2011 .

[6]  Georges M. Fadel,et al.  Design and Manufacturing Functionally Gradient Material Objects With an Off the Shelf Three-Dimensional Printer: Challenges and Solutions , 2015 .

[7]  C. Gosselin,et al.  Additive Manufacturing and Multi-Objective Optimization of Graded Polystyrene Aggregate Concrete Structures , 2015 .

[8]  Carolyn Conner Seepersad,et al.  Applications of additive manufacturing in the construction industry – A forward-looking review , 2018 .

[9]  Paulo Jorge Da Silva bartolo,et al.  Functionally Graded Structures through Building Manufacturing , 2013 .

[10]  Jean-Marc Linares,et al.  Bio-inspired method based on bone architecture to optimize the structure of mechanical workspieces , 2018, Materials & Design.

[11]  T. Grasser,et al.  Continuous Property Gradation for Multi-material 3D-printed Objects , 2018 .

[12]  GramazioFabio,et al.  Complex concrete structures , 2015 .

[13]  Freek Bos,et al.  Additive manufacturing of concrete in construction: potentials and challenges of 3D concrete printing , 2016, International Journal of Civil Engineering and Construction.

[14]  Christoph Gehlen,et al.  Particle-bed 3D printing in concrete construction – Possibilities and challenges , 2018, Cement and Concrete Research.

[15]  R. Breitenbücher,et al.  Hybrid Concrete Elements with Splitting Fiber Reinforcement Under Two-Dimensional Partial-Area Loading , 2018 .

[16]  Mohamed Maalej,et al.  Introduction of Strain-Hardening Engineered Cementitious Composites in Design of Reinforced Concrete Flexural Members for Improved Durability , 1995 .

[17]  E. Bosco,et al.  Ductility of 3D printed concrete reinforced with short straight steel fibers , 2018, Virtual and Physical Prototyping.

[18]  Z. Ahmed,et al.  Design of a 3D printed concrete bridge by testing , 2018, Virtual and Physical Prototyping.

[19]  Satish T. S. Bukkapatnam,et al.  Crafting large prototypes , 2001, IEEE Robotics Autom. Mag..

[20]  Andrew W Gale,et al.  A design tool for resource-efficient fabrication of 3d-graded structural building components using additive manufacturing , 2017 .

[21]  M. B. Bever,et al.  Gradients in composite materials , 1972 .

[22]  Behrokh Khoshnevis,et al.  Automated construction by contour craftingrelated robotics and information technologies , 2004 .

[23]  Cho,et al.  Local Composition Control in Solid Freeform Fabrication , 2001 .

[24]  Annika Raatz,et al.  Development of a Shotcrete 3D-Printing (SC3DP) Technology for Additive Manufacturing of Reinforced Freeform Concrete Structures , 2018, RILEM Bookseries.

[25]  Richard A. Buswell,et al.  Developments in construction-scale additive manufacturing processes , 2012 .

[26]  Brian Mellor,et al.  Multiple material additive manufacturing – Part 1: a review , 2013 .

[27]  Kah Fai Leong,et al.  3D printing trends in building and construction industry: a review , 2017 .

[28]  Behrokh Khoshnevis,et al.  Mega-scale fabrication by Contour Crafting , 2006 .

[29]  Mohamed Maalej,et al.  Corrosion Durability and Structural Response of Functionally-Graded Concrete Beams , 2003 .

[30]  Freek Bos,et al.  Rethinking reinforcement for digital fabrication with concrete , 2018, Cement and Concrete Research.

[31]  Nicolas Roussel,et al.  Digital Concrete: A Review , 2019, Cement and Concrete Research.

[32]  Glaucio H. Paulino,et al.  Functionally-graded fiber-reinforced cement composite: Processing, microstructure, and properties , 2008 .

[33]  Yuen-Shan Leung,et al.  Approximate Functionally Graded Materials for Multi-Material Additive Manufacturing , 2018, Volume 1A: 38th Computers and Information in Engineering Conference.

[34]  Freek Bos,et al.  Hardened properties of 3D printed concrete: The influence of process parameters on interlayer adhesion , 2019, Cement and Concrete Research.