BS EN 771-6-2005 pdf download.Specification for masonry units Part 6 : Natural stone masonry units.
5.5 Apparent density
The manufacturer shall declare the apparent density of six specimens sampled in accordance with Annex A and tested in accordance with EN 1936.
NOTE The term apparent density used in relation to natural stone units is the same Property declared as gross densdy in EN 771 Parts ito 5.
5.6 Mechanical strengths
5.6.1 CompressIve strength
The manufacturer shall declare the mean compressive strength and, when relevant, the normalised compressive strength. In addition the manufacturer may declare the characteflstic compressive strength (5 % fractile). In addition, the manufacturer shall declare whether the natural stone masonry unit is classified as Category I or Category II.
The normalised compressive strength procedure of a natural stone masonry unit is given in EN 772-1:2000. Annex A.
When the natural stone masonry units are sampled from a consignment in accordance with Annex A and tested in accordance with EN 772-1 and conditioned in accordance with EN 772-i :2000, 7.3.3 b), then the mean compressive strength of the specified number of natural stone masonry units from a consignment shall be not less than the declared compressive strength and no individual unit shall have a compressive strength of less than 80 % of the declared mean value.
When it Is not convenient to test whole units the test specimen may be cubes with (70 ± 5) mm or (50 ± 5) mm edge or right circular cylinders with diameter and height which are equal to (70 ± 5) mm or (50 ± 5) mm.
Sawn test specimens shall be representative of the original unit section.
The dedaration shall relate to and indicate the intended orientation of natural stone masonry units as tested and the method of bedding the units. Where, due to its means of formation the strength properties of the stone are not isotropic, e.g. due to presence of bedding planes, it may be necessary to declare the compressive strength normal to more than one face of the test specimen. If the grinding process significantly alters the contact area of the faces tested or if the flatness tolerance cannot be achieved and the capping procedure is thereby used this shall be declared.
The size and shape of the specimen tested shall be reported.
NOTE When shape factors are available e.g. in a database to be used to normalize the compressive strength from cul cubes or q,linders. these may be used.
5.7.2 Declaration based on fixed values
When no declaration is made in accordance with 5.7.3 the characteristic initial shear strength of the
unit in combination with mortar may be declared by reference to EN 998-2:2003. Annex C.
5.7.3 Declaration based on tests
The characteristic initial shear strength of the unit in combination with a specific type of mortar specified in accordance with EN 998-2 may be declared based on the tests on masonry units sampled from a consignment in accordance with Annex A and tested in accordance with EN 1052-3. The charactenstic initial shear strength shall not be less than the declared value.
NOTE Bond strength depends on the mortar, the masonry unit and the workmansh.
5.8 Flexural bond strength
When relevant to the uses for which natural stone masonry units are put on the market, the ftexural bond strength of masonry made with the units and mortar specified in accordance with EN 998-2 shall be declared. The declaration shall give the value of the characteristic flexural strength of the masonry combination for either a plane of failure perpendicular to the bed joints or a plane of failure parallel to the bed joints or both, as relevant, and the mortar specification for which the declaration is valid. When natural stone masonry units are sampled in accordance with Annex A and tested in combination with the specified mortar, in accordance with EN 1052-2, the characteristic Ilexural strength of the relevant masonry specimens shall not be less than the declared value for the plane of failure.
5.9 Open porosity
The manufacturer shall declare the average open porosity of six specimens sampled in accordance with Annex A and tested in accordance with EN 1936.
5.10 Water absorption coefficient by capillarity
When relevant for the uses of the product th€ water absorption coefficient due to the capillary action shall be dedared by the manufacturer. When the natural stone masonry units are sampled from a consignment in accordance with Annex A and tested in accordance with EN 772-11 then the mean water absorption of the specified number of natural stone masonry units shall be not greater than the declared water absorption.
When it is not convenient to test whole units the test specimen may be cubes with (70 ± 5) mm edge or cylinders with diameter and height which are equal to (70 ± 5) mm. The area of the base to be immersed shall be calculated by measurements of two medians to the nearest 0,1 mm. The mass of the specimen shall weigh to the nearest 0,01 g. The specimens shall be weighed a minimum of 7 times, at the following intervals ±5 %:BS EN 771-6-2005 pdf download.