EN 846-14-2012 pdf download.Methods of test for ancillary components for masonry – Part 14:Determination of the initial shear strength between the prefabricated part of a composite lintel and the masonry above it.
6.1 Apparatus capable of measuring the cross sectional area of the specimens to an accuracy of 1 %.
7 Preparation and curing of specimens
7.1 Preparation of masonry specimen
Prepare specimens, according Table 2 and Figure 1. 11 h < 200 mm, type I specimens shall be used. The top and bottom parts consist of two pieces of the prefabricated part of the composite lintels with the intended upper bed face towards the respective mortar joints. The middle part of the specimen consists out of a masonry unit, If the upper bed face of the piece of the prefabricated part of the composite lintel is not obvious or declared then the top and bottom part shall have the same orientation. If hj> 200 mm, type Il specimens may be used. The bottom parts consist of a piece of the prefabricated part of the composite lintels with the intended upper bed face towards the mortar joints. Where for practical purposes it is necessary to cut units, ensure that the faces of the unit to be mortared are representative of the unit as a whole. The length I of the piece of the prefabricated part of the composite lintel shall correspond with the length of the masonry unit I S 300 mm.
Record the method of conditioning the prefabncated part of the composite hntels prior to laying. Build the specimens within 30 mm after completion of the conditioning of the units. Use mortar mixed not more than 1 h beforehand unless it is designed to be used over a more prolonged period. The bearing surfaces of the masonry units shall be wiped clean of any adherent dust. The lower piece of the prefabricated part of the composite lintel shall be laid on a clean level surface. The masonry unit shall be laid so that a rinal mortar jo4nt thickness of 8 mm to 15 mm, representative of masonry with conventional mortar joints, or of 1 mm to 3 mm, representative of masonry with thin layer mortar joints, is attained. The masonry unit shall be checked for linear alignment and level using a set-square and spirit level. Excess mortar shall then be struck off with a trowel. The procedure for the masonry unit shall be repeated for the top piece of the prefabricated part of the composite lintel. The intended bonding faces of the pieces of the prefabncated part of the composite lintel shalt be in contact with the mortar (the faces that are normally visible shall stay visible).
7.2 Curing and conditioning of the specimens
Immediately after building, pre-compress each specimen by an uniformly distributed mass to give a vertical stress between 2,0 NImm2 x i03 N/mm2 and 5,0 N/mm2 x 10 N/mm2. Then cure the specimens and maintain them undisturbed until testing. For other than lime based mortars, prevent the test specimens from drying out during the curing period by close covering with polyethyiene sheet, and maintain the specimens undisturbed until testing, unless otherwise specified. Test each specimen at an age of 28 days i 1, unless otherwise specified for lime based mortars, and determine the compressive strength cf the mortar at the same age following EN 1015-11.
8 Procedure
8.1 Placing the specimens in the testing machine
Support the end units of each specimen in the test apparatus in accordance with Figure 2. For this, use pieces of steel at least 12 mm thick, with an appropriate capping if necessary, to ensure good contact. The diameter of the roller bearings shall be 12 mm with a length of at least the width of the unit. Apply the load through a ball hinge placed in the centre of the top central steel plate.EN 846-14-2012 pdf download.