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Bacterial healing of cracks in cementitious materials

PhD defence, Monday 21 October 2019

2019.10.21 | Vibeke Lundbye Westphall

Søren Dollerup Nielsen

Bacterial healing of cracks in cementitious materials

PhD defence, Monday 21 October 2019. Søren Dollerup Nielsen

During his studies, Søren Dollerup Nielsen worked on the development of a microbially induced self-healing cement utilizing CaCO3 precipitating endospore forming bacteria. The endospores of these bacteria were embedded inside superabsorbent polymers (SAP) as protective agent and as a product that can be readily added to the cement mixture before casting. The ingress of water when cracks occur in the hardened cementitious material induces the SAP to swell up and seal the cracks while creating an environment where the bacterial endospore will germinate, grow and precipitate CaCO3 to effectively heal the cracks. The development of a microbially induced self-healing cementitious material required the advancement of several novel techniques including microcalorimetry of microbial heat production, optical sensing of pH and O2 inside cracks of hardened cement paste, and the synthesis of novel pH responsive SAPs.

The new research findings contribute to the development of a microbially induced self-healing cement paste for use in the oil industry as a smart material for well cementing in the deep subsurface and for well abandonment purposes.

The PhD degree was completed at the Center for Geomicrobiology / Section for Microbiology, Bioscience, Science and Technology, Aarhus University.

This résumé was prepared by the PhD student.

Time: Monday, 21 October 2019 at 15.00
Place: Aud. G1 1532-116 (first part), G3 1532-218 (second part) Department of Mathematics
Title of PhD thesis: Microbiallly Induced Healing of Oil Well Cement
Contact information: Søren Dollerup Nielsen, e-mail: soren.dollerup@bios.au.dk, tel.: +45 22305334
Members of the assessment committee:
Associate Professor Henk M. Jonkers, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Netherlands
Associate Professor Kristian Koefoed Brandt, Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
Associate Professor Mark Bayley, Department of Bioscience, Aarhus University (chair)
Main supervisor:
Associate Professor Hans Røy, Department of Bioscience, Aarhus University
Co-supervisor:
Associate Professor Kasper Urup Kjeldsen, Department of Bioscience, Aarhus University
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1521, 8000 Aarhus C.

PhD defence
12183 / i43