PhD position: Evolution of transport, microstructural and hygro-mechanical properties of...

In the Belgian concept of geological disposal of radioactive waste in a clay host rock, concrete tunnel liners play a crucial role in ensuring safety during and after (retrievability) the operational phase of the disposal system. Thus the expectation is that the liners offer mechanical stability at least for several hundreds of years. However, concrete is not in geochemical equilibrium with the surrounding geological environment resulting in a gradual evolution of its physical, chemical and mechanical properties, which may not be desirable from safety point of view. Furthermore, the above, that is, chemically induced degradation of concrete structures are equally applicable for near-surface disposal facilities, where concrete is the primary material of construction. Thus the study of long term chemo-mechanical behaviour of concrete is an important undertaking and will offer extremely valuable input and contribute to the safety of the Belgian geological disposal program.

The objective of this PhD is to contribute to an improved understanding of coupled chemo-hygro-mechanical behavior of CEM I blended with silica fume and blast furnace slag (applicable for geological disposal) type concrete. Combined leaching and carbonation are the main degradation processes under consideration. These processes are relevant for both deep geological disposal (Phung et al. 2019), where concrete tunnel liners may potentially be subjected to simultaneous leaching and carbonation (due to high carbonate content in the host rock), as well as near surface disposal applications. The combined process is by no means trivial in that opposing effects may be encountered. For instance, leaching causes an increase in porosity (Phung et al. 2015b) and a decrease in strength, whereas carbonation causes a decrease in porosity (Phung et al. 2015a) and an increase in strength. Yet another example is the clogging of some pores caused by the carbonation, which can lead to a decrease in transport properties, but also cause the formation of fractures due to carbonation shrinkage. These coupled processes may have a significant impact on the mechanical behavior, which requires a multiscale experimental and numerical chemo-mechanics approach to reach a thorough understanding of all aspects of these complex coupled processes.

Job description

• You prepare a doctoral thesis, which will be supervised by promotors from University of Lille, France; Ghent University, Belgium and mentors from SCK CEN.
• The PhD project is jointly funded by SCK CEN and ONDRAF/NIRAS.
• You conduct research and publish scientific articles related to this PhD research project.
• You will be part of an international, interdisciplinary team.
• You will mainly work at SCK CEN in Mol, Belgium and partially work at University of Lille, France, Ghent University, Belgium.

Required profile

• You hold a Master degree in civil engineering or related degrees. Students in the final year of their degree can also apply.

• You have an excellent background in cement/concrete degradation (both modelling and experimental).
• You have a strong interest in interdisciplinary research.
• You are quality-oriented, conscientious, creative and cooperative.
• You have mastered the English language, both in writing skills and oral presentations
• You are interested in working in an international environment.

We offer

• A doctoral scholarship for a period of 4 years with competitive salary
• A dynamic and stimulating work environment
• Involvement in a European project (Horizon 2020 “MAGIC”)
• Stimulation to self-improvement by encouraging participation in courses, workshops and conferences
• Close supervision and guidance in conducting the planned research by a supervisory team from SCK CEN, University of Lille and Ghent University.

How to apply?

Please follow the application guidelines posted on SCK CEN’s website: https://academy.sckcen.be/en/Your_thesis_internship/PhDNIRAS_thesis#guidelines

Before applying, it is compulsory to first contact the SCK CEN mentor for further information. When contacting the mentor, please prepare an application file giving following information:

• A short CV with a summary of your career
• A motivation letter
• A copy of relevant diplomas
• Transcript of study records

• Master of sciences in engineering
• Master of sciences

4 years

R&D Disposal

Phung Quoc Tri

[email protected]

+32 (0)14 33 32 40

Li Xiang Ling

[email protected]

+32 (0)14 33 27 76

Shao JianFu

[email protected]

Wan-Wendner Roman

[email protected]