PhD student position in Biologically induced degradation of sprayed concrete in subsea tunnels

Full-time temporary employment. The position is limited to a maximum of five years, including teaching 20% of the employment time.

Description

Subsea road tunnels are increasingly used to connect people all around the world. In for example Norway, over 30 subsea tunnels have been built since the early 1980’s. Several new subsea tunnels are also planned in the near future in Norway within the ferry-free coastal route E39 project. Sprayed concrete is used for rock support in road tunnels. To increase the strength properties, the sprayed concrete is reinforced with fibers, commonly made of steel. Degradation of the sprayed concrete and its fibers due to chemical and microbial reactions can result in destabilization of the rock mass, leading potential safety risks, increased costs for maintenance and reduced overall lifetime of the tunnel.

A novel deterioration process has recently been discovered in several Norwegian subsea tunnels resulting in rapid degradation of the concrete matrix and destructive corrosion of the steel fibers in areas with leakages of saline groundwater. Thick microbial biofilms are involved in this degradation process. However, knowledge about the microbial communities and degradation mechanisms is yet poor. In order to understand and ultimately prevent such degradation processes, thorough biofilm microbiological and chemical studies are necessary. The microbial biofilm communities and their activities involved in degradation of concrete and fibers are complex and require detailed investigations using molecular microbial methods in conjunction with thorough chemical measurements. In this research plan, we propose studies of spatial and temporal patterns, using a suite of molecular microbial methods and chemical measurements, for assessment of the composition, diversity, stratification and activity of the biofilm microbial communities in relation to the associated degradation of concrete and fibers. Studies will be performed on-site in the subsea tunnels as well as at defined conditions in laboratories.

As a PhD student you are expected to work independently; have the ability to plan and organise your work; to be able to work in close collaboration with other group members and partners; and to be able to communicate scientific results, both orally and in written form in English. Knowledge of Swedish and/or Norwegian is advantageous due to close collaboration with Swedish and Norwegian stakeholders.

You are expected to participate in teaching Bachelor and Master level courses in the field of civil and environmental engineering. Bachelor courses are taught in Swedish, and applicants that do not have Swedish as a native language should be able to teach in Swedish within two years of employment. Chalmers offers courses in Swedish language.

Nr of positions available : 1