EN 1766-2017 pdf download.Products and systems for the protection and repair of concrete structures – Test methods – Reference concretes for testing.
Moulds for producing concrete specimens, of non-absorbent, rigid material, not attacked by cement paste, of a size 300 mm x 300 mm x 100 mm or other sizes specified in individual test method standards, corresponding to the property to be tested, shall be used.
4.3 High frequency vibrating table
Or vibration rod suitable for compaction of the concrete in the moulds.
4.4 Grit blasting equipment
It shall comply with the following:
a) air pressure approximately 0,5 MPa;
b) nozzle diameter 8 mm to 12 mm;
c) the spread angle of the nozzle shall be sufficient to prevent the jet from cutting deeply into the concrete surface. This shall be demonstrated by preliminary test.
NOTE As alternative, high pressure water-blasting equipment, capable of operating with or without the
addition of grit, can be used subject to preliminary tests to confirm that the required surface texture can be
achieved.
4.5 Surface roughness measuring equipment
a) Measuring cylinder. 01(25 ± 1) ml total capacity and 20mm maximum internal diameter;
b) disc, comprising a flat wooden disc (65 ± 5) mm in diameter with a hard rubber disc of the same diameter (1,5 ± 0,5) mm thick stuck to one face, the reverse face being provided with a handle (see Figure 1).
5.4 Admixtures
Admixtures according to EN 934-2 shall be used.
5.5 Grit for surface preparation by blasting
Commercial grit for grit-blasting of concrete shall be used, with grain size within the range of 0,25 mm to 1,0 mm. The grit shall not contain ferrous components such as chilled cast iron slag, which are prone to rusting.
5.6 Silica sand for measuring roughness
Silica sand with a grain size of 0,05 mm to 0,1 mm, dried to a constant weight, shall be used.
6 Reference concrete mixes
6.1 General
This standard specifies eight types of reference concrete, defined by the maximum size of the aggregate and mix proportions. The reference concrete is chosen according to the type of product or system for the protection and repair of concrete structures and to the related test methods standards.
NOTE 1 The water taken into account hereafter in the water/cement ratio is the added water plus the water already contained in the admixtures and the additions.
Workability should be appropriate to achieve adequate placing of concrete with freedom from bleeding or segregation. Any special requirements for surface finish of placed specimens for particular test methods using reference concrete samples will be stated in those test methods.
Admixtures conforming to EN 934-2 are permitted to give a workable concrete mix to meet the requirements of Table 1 or to confer adequate freeze—thaw resistance by entrainment of air.
NOTE 2 The application of a suitable plasticizer or super plasticizer conforming to EN 934—2 is likely to be required to achieve optimum compaction, as described in 6.4.
6.2 Reference concrete with 16 mm or 20 mm aggregate
6.2.1 Compositions and properties (see Table 1)
6.2.1.1 Type C (0,40)
The mix shall contain 4 10/425 kg/rn3 cement and have a water/cement ratio of 0,40. Mixes shall have a
28 day mean compressive strength measured according to EN 12390-3 of (60 ± 5) N/mm2 for cubes and
(50 ± 5) N/mm2 for cylinders, a median tensile bond strength by pull off according to EN 1542 greater
than 3 N/mm2.
6.3 ReFerence concrete with 8 mm or 10 mm aggregate
6.3.1 Compositions and properties (see Table 1)
6.3.1.1 Type MC (0,40)
The mix shall contain 455/470 kg/rn3 cement and have a water/cement ratio of 0,40.
After 28 days the reference concrete shall have an average tensile bond strength determined by pull off according to EN 1542 with a minimum value of 3,0 N/mm2, but not for any individual result. The pull off test shall be carried out on the prepared concrete surface immediately before applying the material to be tested, using at least one substrate specimen from each batch of concrete. At least one in every 15 specimens shall be tested.
NOTE The requirements are usually met by a concrete with a compressive strength which satisfies class
C50/60, as specified in EN 206.
6.3.1.2 Type MC (0,45)
The mix shall contain 395/410 kg/rn3 cement and have a water/cement ration of 0,45.
After 28 days the reference concrete shall have a median tensile bond strength determined by pull off according to EN 1542 greater than 2,5 N/mm2, but not for any individual result. The pull off test shall be carried out on the prepared concrete surface immediately before applying the material to be tested, using at least one substrate specimen from each batch of concrete. At least one in every 15 specimens shall be tested.
NOTE The requirements are usually met by a concrete with a compressive strength which satisfies class
C 40/50, as specified in EN 206.
6.3.1.3 Type MC (0,70)
The mix shall contain 290/305 kgJm cement and a water/cement ratio of 0,70 ± 0,05. Mixes shall have a 28 day mean compressive strength measured according to EN 12390-3 of (30 ± 5) N/mm2 for cubes and (25 ± 5) N/mm2 for cylinders and, when applicable, a median tensile bond strength by pull off according to EN 1542 greater than 1,5 N/mm2.
6.3.1.4 Type MC (0,75)
The mix shall contain 235/240 kg/rn3 cement (10/8 mm) and a water/cement ratio of 0,75 ± 0,05.
Mixes shall have a 28 day mean compressive strength measured according to EN 12390-3 of
(25 ± 5) N/mm2 for cubes and (20 ± 5) N/mm2 for cylinders and, when applicable, a median tensile
bond strength by pull off according to EN 1542 greater than 1,2 N/mm².EN 1766-2017 pdf download.