PhD researcher “Material development for earth based impact printed structures”
ETH Zurich
State University, Browse similar opportunities
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State University, Browse similar opportunities
The Chair of Sustainable Construction at ETH Zurich intends to ground sustainability in the disciplines of the built environment. We want to foster international collaboration among the different stakeholders involved in architecture, engineering and construction and to promote appropriate application of sustainable construction materials during the entire life cycle of buildings and infrastructure.
The PhD position is funded through the ETH grant “impact printed structure”. The project is combining natural earth-based building material with cutting-edge digital design and robotic fabrication technology and is a collaboration between three ETH research groups: the Chair of Sustainable Construction, Gramazio Kohler Research, and the Robotic Systems Lab.
Earth construction has an extensive building tradition across the World. However, it is lacking technological development and is a highly manual, slow and formwork-dependent building process. Thus, such construction in Switzerland faces implementation difficulties due to high labour costs. We believe that pursuing an automated workflow applied to real scale in situ earthen construction can make sustainable building processes more viable, simultaneously opening up new opportunities through digital integration.
We propose a contemporary reinterpretation of cob walls. In a wet state, earth blocks are stacked onto each other creating an interlocking structure. The further strength gain can then be achieved through internal curing and self-dessication to speed up the natural drying process. The current PhD objective is to develop a strategy for such self-desiccation.
Controlling the stiffness of earthen compounds to achieve the desired consistency at the desired moment of the construction process has generated a large amount of research. The Chair of Sustainable Construction has been pioneering the development of Self Compacted Clay Concrete (SCCC) where the following functions are required 1) good workability at the fresh state with low water content; 2) the ability to remove the formwork within 24 h; 3) a compressive strength suitable for wall elements [Ouellet-Plamondon et al, 2016]. Different strategies have been tested through the use of biopolymers such as alginate [Pinel et al., 2017] or more vernacular products [Vissac et al, 2012], as well as mineral additives [Landrou et al, 2018]. Implementation of these advanced clay materials into 3D printing has been tested [Perrot et al., 2018]. In all current applications, the deflocculation/coagulation process is used only to process the material, in the sense that it allows obtaining a fluid clay paste that stiffens on-demand once printed or cast. But the drying of the material that will provide the final strength of the earth wall is only achieved through air exposure (and therefore takes time). Except when the necessary internal drying has been achieved through the use of Calcium Sulfo Aluminate cement [Ouellet-Plamondon et al, 2016]. However, these binders have a similar environmental impact as cement, therefore the current PhD research will focus on the development of alternative binders reaching the same performance of self-desiccation and strength without the need for curing.
We offer working in an exciting interdisciplinary project with high visibility. Work is carried out in a small research group at ETH Zurich equipped with excellent computational and lab facilities. Supervision will be close but allow independent work. English and German are the working languages of the institute. The duration of the project is three years.
Useful references:
C. M. Ouellet-Plamondon, G. Habert. 2016. Self-Compacted Clay Based Concrete (SCCC): Proof-of-Concept, Journal of Cleaner Production, 117, 160-168
A. Perrot, D. Rangeard, E. Courteille 2018. 3D printing of earth-based materials: Processing aspects. Construction and Building Materials, 172, 670–676
A. Pinel, Y. Jorand, C. Olagnon, A. Charlot, E. Fleury, 2017. Towards poured earth construction mimicking cement solidification: demonstration of feasibility via a biosourced polymer. Materials and Structures, 50, 224-230.
A. Vissac, L. Fontaine, R. Anger, 2012. “Recettes traditionnelles & classification des stabilisants d’origine animale ou végétale, report, Grenoble: CRAterre-ENSAG.”
G. Landrou, C. Brumaud, G. Habert, 2018. Influence of Magnesium on deflocculated kaolinite suspension: mechanism and kinetic control, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 544, 196-204..
G. Landrou, C. Brumaud, M. L. Plötze, F.Winnefeld, G. Habert, 2018. A fresh look at dense clay paste: deflocculation and thixotropy mechanisms, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 539, 252-260.
We welcome highly motivated and curious applicants holding a MSc in chemical or civil engineering, materials or earth sciences or similar disciplines. The ideal candidate has a strong interest in sustainable construction, robotic, clay materials and alternative cementitious products. Fluency in spoken and written English is a requirement. German speaking is an added value.
ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow.
We look forward to receiving your online application with the following documents:
Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.
We seek to start on March 1, 2021 or by agreement.
For further questionsplease contact Prof. Dr. Guillaume Habert (habertg@ethz.ch ) (please do not send applications). More information about the Chair of Sustainable Construction is available online: www.sc.ibi.ethz.ch .
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