Skip to main content
European Commission logo

Non-destructive testing and evaluation of adhesion and surfaces (VSS2006/514_OBF)

Switzerland Flag
Complete with results
Geo-spatial type
STRIA Roadmaps
Vehicle design and manufacturing (VDM)
Infrastructure (INF)
Transport mode
Road icon
Transport sectors
Passenger transport,
Freight transport


Background & Policy context

Applied on concrete bridges, non-destructive testing like ground penetration radar and thermography obviously provide useful information for the evaluation of the total structure consisting of sealing systems and bituminous layers. Since the collection of drill core samples provide local information only, large areas can be tested continuously with the above mentioned methods. In addition, sampling of drill cores always leaves damages.

Basically every avoided drill work on bridges is a good sampling. Destruction free testing methods enable the renouncement or at least reduction of sampling drill cores. First experiences in this field already exist. Nevertheless, there is no systematic adjustment of testing methods relative to normative systems in Switzerland that provide guidelines for their standardization.


To improve the application of non-destructive testing in order to avoid damages on tested objects, as well as to reduce the number of samples is the main objective of this project. The project should:

  • determine the detection limit in observing damages (extent and size) like e. g. constructional defects in concrete, damages in bituminous layers, insufficient connectivity between layers etc.
  • determine the detection limit of humidity in concrete and adhesion mediators
  • determine the detection limit of insufficient connectivity (lacking versus insufficient connectivity, extent of damage)
  • discuss obtained results about the surface structure
  • discuss influences of determined damages on sealing systems
  • evaluate the suitability of applied destruction free testing methods
  • recommend a range of application for the ZFP testing methods
  • propose requirement values on the basis of obtained testing results and analysis of available data

Methods used

The power of non-destructive testing methods to assess (ZFP), the comparison with other test methods is essential. Here are examples:

Humidity: thermography / CM measurement, isotopic probe

Porosity: thermography / Torrent, determination of porosity on core

Texture: Laser / sandy spot

Open GPR / leaf rake / window: defects / voids

Further ZFP methods are:

  • IR spectral analysis (detection of water and other substances harmful)
  • Ultrasound (detection of defects / cavities)


Parent Programmes
Institution Type
Public institution
Institution Name
Swiss Government: State Secretariat for Education and Research
Type of funding
Public (national/regional/local)


Cross correlation between the measuring campaigns and the measures on the laboratory superstructures should obtain the aimed results.

The limits of the measuring were detected in the framework of the project.  To determine the limit of detection of the various ZFP pattern surfaces are created. In a covered hall a pattern area of approximately 10 x 20 m is concreted. Various concretes with different water / cement factor are used. In addition, the surface is treated differently. This results in a total of 6 faces with different porosities and textures of the surface. In 2 of the 6 sample surfaces (eg "concrete 1") the four to be examined seal species are applied:

  • PBD-sealing
  • FKL from PU
  • FLK acrylic

In the 4 remaining sample surfaces  only the bonding agent is applied. It was  assumed that the characteristics of the concrete surface are no longer relevant under the EP-bonding agent. Incorporation of FLK-seals on these sample areas would not provide any further information. By contrast, the PBD-seal is applied to bituminous adhesive on all variants of the concrete substrate. This choice leads to 12 pattern fields.

These 12 selected fields created 4 different types of defects, which differ in their size. We know from practice that already can cause pores in the size of the rice grain damage. The 12 individual fields are divided into 4 sub-fields, which differ as follows:

  • Subfield 1 no flaws
  • Subfield 2 defects in the size of a rice grain
  • Subfield 3 flaws in the size of a grain of corn
  • Subfield 4 flaws in the size of a cherry

These 48 subfields that the above figures (porosity, moisture, voids, texture) will differ in terms of porosity and texture of the concrete surface, sealing, and size of defects measured by conventional test methods and ZFP. These test methods are used in the following phases of the creation of the panels:

  • On the concrete surface
  • The bonding agent
  • On the seal
  • On the protective layer
  • Measurements on objects

There are also here used "conventional" testing methods to evaluate the results of the ZFP:

In addition, the following wer used "conventional" tests:

  • Sand stain method (texture depth)
  • Torrent examination (porosity)
  • CM measurements (moisture)
  • Isotope probe (humidity)


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


Contribute! Submit your project

Do you wish to submit a project or a programme? Head over to the Contribute page, login and follow the process!