PhD student in Engineering Science (M/F) The University of Luxembourg

PhD student in Engineering Science (M/F)

Application End : Thursday March 31 2011

The University of Luxembourg is looking within its Faculty of Science, Technology and Communication for outstanding candidates committed to excellence in research, opento interdisciplinary work, and helping to develop an emerging academic institution.

PhD student in Engineering Science (M/F)

• Financed by the Luxembourgish AFR (Aide Formation Recherche) fellowship (further information and guidelines on http://www.afr.lu)
• 3 year fixed-term contract, renewable one year under justified circumstances, 40h/week
• Employee status

Theme : Load bearing capacity of hybrid fibre reinforced concrete

Steel fibre reinforced concrete (SFRC) is concrete containing fibrous steel material which increases its structural integrity. It contains short discrete fibres that are uniformly distributed and randomly oriented. The character of fibre reinforced concrete changes with varying concrete formulations, fibre materials, geometries, distribution, orientation and densities. Also the marked brittleness with low tensile strength and strain capacities of high-strength concrete (HSC) can be overcome by the addition of steel fibres.
Within this project the mechanical properties of normal and high-strength steel fibre reinforced concrete realized as hybrid formulations combining different types and geometries with different concrete matrixes will be investigated. First tests already realized at the Laboratory of Solid Structures at the University of Luxembourg result in superior composite performance compared to their individual fibre-reinforced concretes. The obtained results confirm that the flexural strength at small crack widths and the ductility of the hybrid fibre concrete is improved in comparison with individual fibre reinforced concrete. The research results show that a certain content of fine particles such as fly ash is necessary to evenly disperse fibres. The different sizes of steel fibre contributed to different mechanical properties. Additions of a small fibre type had a significant influence on the maximal load bearing capacity while a large fibre type will mostly affect the post-cracking behaviour. There is a synergy effect in the hybrid fibre system by optimizing their combinations.
For the here planned investigations, as well steel-micro fibres as steel-macro fibres with short straight steel fibres and long hooked-end steel fibres will be used. First the bond slip characteristic for the fibres bonded in different concrete formulations with varying fine proportions and varying grain size distributions will be examined. Then, the load bearing capacity of small beam and plate elements will be analysed and the mechanical properties described by a theoretical model. Finally, a few applications in large scale tests will be necessary to confirm previous results.
The project will be realized in cooperation with the “Wilhelm Dyckerhoff Institut” in Wiesbaden of the Dyckerhoff AG in Germany.

Profile

• Master of Science (or equivalent) in Engineering Science (civil engineer or mechanical engineer)
• The University of Luxembourg is set in a multilingual context. It is desired that the candidate will have a working knowledge in at least two of the following languages: English, French, and German.

Offer

• A dynamic team in an emerging academic institution
• Excellence in research
• Interdisciplinary work

Applications letters with clear referral to the concerned position must be sent by ordinary mail or email until March 31st, 2011 to the following address:
Prof. Danièle Waldmann
Université du Luxembourg – Campus Kirchberg
6, rue Richard Coudenhove-Kalergi
L-1359 Luxembourg
Tel: 46 44 66 5279
Email: daniele.waldmann

The University of Luxembourg is an equal opportunity employer.