PHD Position - Tackling challenges to meet the conflicting requirements in 3D concrete printing


The Department of Structural Engineering of the Faculty of Engineering and Architecture, at Ghent University currently is looking for a PhD researcher to start a PhD on the following granted project:



As formwork represents about half of the overall cost of concrete structures, 3D printing of concrete brings new horizons to the construction sector. The possibility to build without formwork is a major advantage in terms of production rate, architectural freedom and cost reduction. Additionally, 3D printing is expected to lead to more sustainable concrete constructions due to reduced waste generation and more efficient structural design placing materials only where needed.
Although it is clear that 3D concrete printing has potential within the construction sector, some conflicting requirements need to be met. While at the one hand retarders are required for printed concrete to ensure that the concrete does not harden while being transported and before being printed, on the other hand accelerators are needed to ensure appropriate setting of the concrete once printed. Moreover, the compressive strength needs to be maximized, which requires a low water to cement ratio, but a certain water content is necessary to ensure appropriate workability. Inside the system, the concrete mix must be flowable but upon pouring it must be buildable to hold itself and subsequent layers. When poured, the mix should set as fast as possible but not too fast to ensure appropriate bonding with subsequent layers. Finally, while it is one of the biggest advantages of 3D printing that no formwork is required, this induces shrinkage and crack formation.
Some concrete mix requirements seem thus contradictory and the challenge is maintaining an appropriate balance. The aim of this project is to obtain an in-depth understanding of the parameters influencing the printability, durability and mechanical properties of (printed) concrete and to tackle the conflicting requirements of 3D printed concrete through the use of an in-house developed multifunctional nozzle able to provide additional mix constituents just before printing to increase the buildability and reduce cracking and with the option to treat the surface of printed layers to improve the bond leading to more durable 3D printed concrete with improved mechanical properties.
More information can be obtained by contacting Prof. Kim Van Tittelboom.

The Magnel Laboratory for Concrete Research at the Department of Structural Engineering of Ghent University is the largest Belgian research center in the field of concrete technology and concrete structures and has a vast and widely-spread international recognition. The research areas focus on different aspects of concrete structures, going from fundamental material research on microscopic and sub-microscopic scale to structural behavior and structural reliability of concrete structures on large scale. The Magnel Laboratory disposes of extensive experimental testing facilities and infrastructures, among which the large strong floor for executing load tests on large-scale elements is a unique instrument. In the context of this project, relevant state-of-the-art equipment is available at the Magnel Laboratory, including rheometers, mixing and pumping facilities, and a large-scale robot set-up for automated production.

The project is funded by BOF-UGent (Special Research Fund - UGent). The project starts as soon as a suitable candidate has been found but certainly before 31 October 2018.
The PhD candidate is offered a 4 year (2+2) appointment in our high-level international research team at Ghent University, enabling to obtain a PhD in Civil Engineering at Ghent University. The candidate will have the possibility to attend international conferences, follow specialized courses, develop a national and international scientific and industrial network and visit different international high-level research institutes.

Applicants should have a master’s degree (or equivalent) in Structural or Civil Engineering, an independent and well-organized working style, well-developed social skills directed towards working in an interdisciplinary team, strong motivation to succeed in scientific research, excellent presentation and scientific writing skills and excellent English language skills (verbally and written). Knowledge of the Dutch language is appreciated.
Applicants should contact Prof. Kim Van Tittelboom as soon as possible, but no later than 1 July 2018.

Prof. Dr. Ing. Kim Van Tittelboom
Department of Structural Engineering
Technologiepark-Zwijnaarde 904, 9052 Ghent, Belgium
T: +32 9 264 55 40 (or secr. +32 9 264 55 35)