Consultation des offres
3D printing of cementitious materials by selective activation method CDD
Context and goal
The Laboratory of Mechanics and Materials of Civil Engineering, a research unit of CY Cergy Paris University is looking for an excellent, highly motivated PhD candidate who will discover the 3D Printing of cementitious materials for a project funded by the French National Research Agency (ANR).
The number of digital construction projects has risen over the last five years and a digital revolution has started to shape the use of concrete  . Several challenges can be overcome by using this technology: environmental, economic, architectural, and societal   .
Since a transformation of the construction sector is key to ensuring that these environmental ambitions are fulfilled, rethinking the use of concrete through 3D printing or additive manufacturing – either directly on-site or precast – is crucial. For the additive manufacturing of construction materials, two techniques can be used: the extrusion of fresh concrete/mortar and the selective binding of a loose particle-bed by a fluid  .
The aim is to focus on the Selective Cement Activation (SCA) method, which consists of activating a powder made from a mix-design of bonding mineral mixed with granulates (sand with or without gravel, depending on the desired application) by injecting or spraying a solution composed of water and additives .
Our goal is to establish and to control the fundamental parameters of the 3D printing by selective cement activation and adapt the process to bio-based construction materials. The project statement is based on three main research goals:
- identify and understand the key parameters to be controlled during the 3D printing activation process;
- adapt and use bio-based construction materials using an innovative 3D printing method;
- validate the uncommon strategy of bringing bio-based construction materials into the mainstream of 3D printing.
To achieve these goals, the material mix-design will be optimized according to the 3D printing process used. The main obstacle to a better selective control of 3D printing by selectively activating the material is the control of the distribution of the aqueous solution (water plus additives) during the printing process. The objective is to obtain a solid interface between the layers, the complete hydration of the anhydrous particles, the homogeneity and so the mechanical performance of the resulting hardened material. The importance of the underlying mechanisms for a comprehensive understanding of the material and process-related influences is essential for this PhD project. The purpose of optimizing the fluid intrusion will be to better understand the path followed by the solution as it penetrates the granular matrix as a function of the mix-design. The PhD student will investigate parameters that may need to be controlled: injection speed, jetting pressure, volume and surface tension of solution drops; the viscosity of the solution; the size of the aggregates, the compactness and the layer thickness of the aggregates bed. Then, the study will be dedicated to the characterisation of printed material (mechanical, thermal, porous network, absorption, physico-chemical properties).
- Master in Materials Sciences, Physics, Civil Engineering
- Experience in the following fields would be appreciated: rheology, cementitious materials, numerical modeling
- Good communication skills
- Some skills in 3D printing and image processing would be a plus for this position.
To apply for this position, a CV, a cover letter and transcript of records for your three last years must be sent to:
- Dr. A. Pierre : firstname.lastname@example.org
- Dr. K. Ndiaye : email@example.com
- Dr. T.T. Ngo: firstname.lastname@example.org
 “G. Geert De Schutter, V. Mechterine, G. Habert, Technical potential of 3D printing, economic and environmental issues, (2018) Cement and Concrete Research.”
 “Dirk Lowke, Enrico Dini, Arnaud Perrot, Daniel Weger, Christoph Gehlen, Benjamin Dillenburger, Particle-bed 3D printing in concrete construction – Possibilities and challenges, Cement and Concrete Research, Volume 112, 2018, Pages 50-65, ISSN 0008-8846.”
 “Timothy Wangler, Nicolas Roussel, Freek P. Bos, Theo A.M. Salet, Robert J. Flatt, Digital Concrete: A Review, Cement and Concrete Research, Volume 123, 2019,.”
 “3D Printing of Concrete: State of the Art and Challenge of the Digital Construction Revolution, Edited by Arnaud Perrot, Wiley Editions, 2019.”
 T. Wangler et al., “Digital Concrete: Opportunities and Challenges,” RILEM Technical Letters; Vol 1 (2016), 2016, doi: 10.21809/rilemtechlett.2016.16.
- Essais de laboratoire
- Milieux poreux