BS/EN 1052-2-2016 pdf download.Methods of test for masonry Part 2 : Determination of flexural strength.
5.1.2 Testing
Determine the compressive strength of a sample of masonry units, using the method given in EN 772-1. For non-autoclaved concrete units determine the compressive strength at the time of testing the masonry specimens.
5.2 Mortar
The mortar, its mixing procedure and its flow value shall conform to the requirements of EN 998-2. unless otherwise specified, and these shall be reported in the test report.
Take representative samples of fresh mortar from the mason’s board to make mortar prisms, to determine the flow value in accordance with EN 1015-3. and to determine the air content in accordance with EN 1015-7. Use the prism specimens to determine the mean compressive strength at the time of testing of the masonry specimens in accordance with EN 1015-11.
6 Apparatus
A testing machine complying with the requirements given in Table 1, and accommodating variations of plane. The testing machine shall have adequate capacity but the scale used shall be such that the ultimate load on the specimen exceeds one 111th of the full scale reading. The machine shall be provided with a load pacer or equivalent means to enable the toad to be applied at the rate specified.
The bearings shall be designed to ensure that contact is provided over the full width of the masonry, for example by using a hollow rubber bolster of at least 7 mm wall thickness and a 10 mm bore containing an 8mm diameter steel rod.
7.2 Construction and curing of the specimens
Build the specimens within 30 mm after completion of the conditioning of the units, using mortar mixed not more than one hour beforehand unless the mortar is designed to be used over a more prolonged period. Construct the specimens to the bond specified. Do not allow the work to be interrupted before corn pletion.
Immediately after building, pre-compress each specimen using a uniformly distributed mass to give a vertical stress between 2,5 x 10 N/mm2 and 5,0 x 10 N/mm2 then cure the specimens, and maintain them undisturbed until testing. For other than lime-based mortar prevent the test specimens from drying out during the curing period by close covering with polyethylene sheet, and maintain the specimens undisturbed until testing unless otherwise specified. Test each specimen at an age of 28 days ± 1 day, unless otherwise specified, and determine the compressive strength of the mortar at the same age, following EN 1015-11. For lime-based mortars an alternative curing regime and period may be necessary and this should be specified.
8 Procedure
8.1 Placing the specimens in the testing equipment
Test the masonry specimen in the vertical attitude under four-point loading (see Figure 1). As an alternative, the specimen can be tested in a horizontal position. If the specimens are to be tested horizontally, weigh the mass m of each specimen to 0,1 kg. The distance between the outer bearings and the end of the specimen shall be greater than or equal to 15 mm. The distance between the inner bearings may be varied to suit the format of the masonry but shall be 0,4 times to 0,6 times the spacing of the outer bearings. The inner bearings shall be located so that they are, as far as practicable, midway between the nearest mortar joints which are parallel to the bearings.
When testing in the vertical attitude ensure that the base of each masonry specimen is free from frictional restraint, for example by setting it on two layers of polytetrafluoroethylene with grease between them or on ball, needle or roller bearings.
When testing in the horizontal attitude care is needed, especially wfth masonry of low flexural strength, to avoid failures in handling and placing in the test machine. It may be necessary to build extra test specimens to ensure that five valid results can be achieved.
8.2 Loading
Increase the flexural stress at a rate between 0,03 N/mm2/min and 0,3 N/mm2/min.BS/EN 1052-2-2016 pdf download.