Reliable, quantitative quality control of hydrophobic treatment of structures

The effects of hydrophobic treatment can now be assessed in terms of quality and quantity on site by means of a special marker that reacts with the silane compound when being added to the concrete or reinforced concrete. The penetration depth of the marker correlates with the penetration depth of the hydrophobing agent, without influencing it. Quality control is fast, reliable, non-destructive and can be easily integrated into the construction process.

In-depth hydrophobic impregnation of structures by means of special silane compounds is an excellent method for protecting cement-bonded construction materials used for road infrastructure, especially in bridge structures. This method helps protect the structures against damage caused by de-icing road salts, capillary water absorption, etc.The present invention provides the first method allowing hydrophobization to be assessed directly on site in terms of quality and quantity. Quality control is fast, reliable, low-destructive and can be easily integrated into the construction process.

In-depth hydrophobic impregnation of structures by means of special silane compounds "preserves" cement-bonded construction materials, such as concrete or reinforced concrete and provides a technically advanced surface protection solution. However, so far it has not been possible to reliably measure and document the success of these protection measures. In addition, considerable investment in time, technology and money has been required in order to visualize these effects. For example, FTIR or pyrolysis gas chromatography can only be carried out in the laboratory, which requires taking larger core samples. Other methods such as the water penetration test according to Karsten, the measurement of the electrical conductivity and the water-repellent effect can be carried out non-destructively and on the structure. But they have little significance because the penetration depth and the distribution of the active ingredient of the silanes cannot be determined in this way.

Researchers at Karlsruhe University of Applied Sciences - Technology and Economics recently developed a marker system, i.e. an optimized composition of a suitable chemical mixture, which is added to the hydrophobing agent before it is applied to the material of the structure. In-depth hydrophobic impregnation of structures is carried out and the marker is incorporated into the polysiloxane film in the structure. The penetration depth of the marker correlates with the penetration depth of the hydrophobing agent, without influencing it. The marker can then be easily identified by using a small core sample (30 - 50 mm) that is analyzed by means of advanced analytical methods, preferably laser-induced plasma spectroscopy (LIBS). The marker consists of a formulation of a metal salt and a complexing excipient in a harmless solvent.

• The effect of the hydrophobic treatment can be assessed:
  • qualitatively
  • quantitatively
  • based on the penetration depth
  • based on the distribution of the agent
• Fast, safe and reliable method
• Can be carried out on site
• low-destructive
• Markers made from harmless chemicals
• Tested in the field

Quality control of hydrophobic treatment of structures as part of building protection measures