BS EN 14891 :- Tensile adhesion strength after freeze-thaw cycle

Preparation of test pieces

  • Apply the liquid water impermeable product to the surface of the substrate 
  • material should be applied in two or more layers, inserting if requested a reinforcing cloth or mesh. 
  • With some
    products, a sprinkling of silica sand into the top layer is required to improve adhesion to the surface.
  • Before applying the adhesive, allow the coated concrete slabs to dry under standard conditions for at least
    24 h, unless the manufacturer gives different instructions.
  •  Apply a thin layer of the adhesive to the water impermeable product with a straight edge trowel. Then apply a
    thicker layer and comb with a notched trowel having 6 mm × 6 mm notches at 12 mm centres. 
  •  After 5 min place nine type V1 tiles on the adhesive at a distance apart of 50 mm and load each tile with
    (20 ± 0,05) N for 30 s.
  •  The trowel shall be held at an angle of approximately 60° to the substrate at a right angle to one edge of the
    slab and drawn across the slab parallel to that edge, in a straight line. 
  • The adhesive between the tiles must
    not be removed.

Prepare the surface of the test pieces 

In addition, a layer of the adhesive
approximately 1 mm thick, shall be applied with a straight edge trowel to the back face of the type V1 tile
before placing. 

 All remaining faces of the slab, including the underside, shall then be sealed with an impervious, waterproof
coating material, such as an epoxide or polyester based product, ensuring complete integrity of the coating on
all the edges and at the junction with the liquid-applied water impermeable product on the upper face.

 Condition the test pieces for 7 days under standard conditions, followed by immersing in water for 21 days
before carrying out 25 freeze-thaw cycles. 

 For each freeze-thaw cycle:

 1) remove the test pieces from the water and lower the temperature to (-15 ± 3) °C within 2 h ± 20 min;

 2) maintain the test pieces at (-15 ± 3) °C for 2 h ± 20 min;

 3) immerse in water at 20 °C ± 3 °C and raise the temperature to (15 ± 3) °C and maintain this
temperature for 2 h ± 20 min.

Repeat the cycle 25 times. After the last cycle wipe the surface of the tiles with a cloth and bond the pull head
plates to the tiles. 

Allow the test pieces to reach standard conditions for at least 7 h and then determine the
tensile strength . 

 Report the results in Newton.

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