Scientific advances and innovation

The long-term objective is to use directly the ND results in the models of penetration of water and aggressive agents, in order to predict the deterioration of the concrete floating part of an offshore windmill.

Expected technical and economic impact

This project is a beginning to improve the NDE survey and assessment of reinforced concrete structure in marine environment, then to improve the diagnosis and prognosis of their lifetime duration for maintenance perspectives.

 

Key project milestones

  • March 2018 - Beginning of the project
  • July 2018 - Report and presentation of the Master2 student
  • October 2018 - Proposition of a structure survey program

Results

Khodor El Achrafi pursued an internship in the LAMES/MAST laboratory (IFSTTAR Nantes). Firstly, he built a database including the mix designs, the conditions of tests and the results of the destructive and nondestructive tests available for lab tests issuing from ORSI-APOS project. He used the models of Tang and Nilsson for the chloride penetration by diffusion in saturated concretes. He analyzed the indicators obtained by fitting the profiles obtained by destructive and non-destructive method. He show the interest in using END profiles in particular to observe the evolution of the diffusion coefficient with time. Secondly, he completed the database by results obtained on site in 2007 by END and destructive methods on cores from 4 reinforced concrete beams in Nantes-Saint-Nazaire harbor. He used the model to predict the chloride penetration in 2018 to test some cases of application and finally to propose a program of nondestructive survey to apply to a RC structure located in tidal zone.

Prospects

It would be particularly interesting to extend this study to the complete durability models describing chloride penetration in tidal zone or in sometimes submerged zone, in order to apply them to the reinforced concrete structures of offshore windmills.