Tensile adhesion strength after water contact in MPa evaluated as the maximum adhesion strength effort that it has by applying, after immersion in water for 20 days, a force at constant intervals of (250 ± 50) N/s at the tile layer type V1 (50 ± 1) mm x (50 ± 1) mm placed on the surface of the adhesive applied on a concrete substrate as specified in EN 1323.

The preparation and instrumentation are identical to those described in the test for the determination of the adhesive strength, times and curing mode change. The end result is the adhesive strength (maximum measurable resistance for unit surface area by pull-off or cutting test (UNI EN 120004). The test method is described in EN 1348 and provides for determination of resistance by pull-off on cementitious adhesive resistance for ceramic tiles. It can be adapted to cementitious premixed adhesives or separate components for interior and exterior floors and walls (UNI EN 1348).

For the tests, you need of 10 square ceramic tiles of dimensions (50 ± 1) mm x (50 ± 1) mm, 10 metal plates of dimensions (50 ± 1) mm x (50 ± 1) mm and minimum thickness of 10 mm with connection to Pull-Off, a Pull-Off able to apply a force of (250 ± 50) N/s, the loads able to exert a force of (20 ± 0.05) N with a section of 50 mm x 50 mm, a notched trowel and a concrete slab (the characteristics are defined in the UNI EN 1323).

To carry out this test, prepare a minimum 2 kg of adhesive (primarily housing for the liquid in the mixer, then the mass and mixed for 30 seconds. After removing the paddle, it is necessary clean it and mix it again finally for 1 min).

Once the adhesive is prepared, apply a thin layer on the concrete slab, with a smooth trowel, then a thicker layer with the notched part of the trowel (with an angle of 60 ° compared to the support). After 5 min., 10 tiles are placed, distancing of 50 mm and loaded with a weight of (20 ± 0.05) N for 30 s. We must make cure the sample under standard conditions (22 ± 2°C and 50 ± 5% relative humidity) for 7 days and subsequently it must be immersed in water (at standard temperature). After 20 days you need to remove the sample from the water, wipe with a cloth and apply the metal plates on the tiles (with a glue high adhesion force). After 7 hours immerse it in water, remove it after 24 hours and immediately perform the adhesion test (with Pull-Off).

After using the Pull-Off you can have different types of breaking, ie:

  • adhesive breaking between adhesive and substrate;
  • adhesive breaking between tile and adhesive;
  • adhesive breaking between tile and adhesion plate;
  • cohesive breaking in the adhesive;
  • cohesive breaking in the support;
  • cohesive breaking in the tile.

 

Material typeStandardTest method
adhesives EN 12004 EN 1348
waterproofing EN 14891 EN 14891 §A.6.3

 

Instruments used to perform the test: Pull-off

 

Tensile adhesion strength after water contact is measured as the maximum adhesion strength effort that you have by applying, after immersion in water for 20 days, a force with a constant interval at the tile layer placed on the adhesive surface applied on a concrete support.