BS EN 13892-7:2003 – Methods of test for screed materials — Part 7: Determination of wear resistance to rolling wheel of screed material with floor coverings
4 Principle Concrete slabs surfaced with screed material and with a defined polyvinyl chloride floor covering are subjected to the repeated passages of a loaded rolling wheel. The specimen fixed to a support moves under a loaded castor wheel in two perpendicular directions at different frequencies. The movement creates normal and shear stress onto the screed material. At the points where the castor turns, shear stress caused by a torsion action is superimposed. During the test, the screed material is influenced by the fatiguing effect of repeated passages of the loaded wheel.
The test is repeated with increasing load. The resistance to the rolling wheel is taken as the maximum load at which the test can be passed without delamination between the floor covering and the screed material.
5 Apparatus – Test rig
5.1 General The principle of the test rig is shown in Figure 1. NOTE The test rig is the same as in EN 1818, except for the swivel castor, the load and the length of the movement.
5.2 Supporting table The supporting table should be level and at least 400 mm x 400 mm. It supports the test specimen while it is moved under the loaded castor, described in 5.3. The supporting table and specimen move under the castor wheel in two directions at right angle, with a longitudinal movement of (210 ± 2) mm with a frequency of (23,6 ± 0,7) cycles/minute, and transverse moment of (150 ± 2) mm and a frequency of (5,8 ± 0,2) cycles/minute. For the wear on the test area to be uniform, the two movements shall not be co-ordinated, but may be driven for example by a common motor with a roller chain transmission as described in ISO 606, with chain wheels with fifty- seven and fourteen teeth respectively. The ratio of the frequencies shall be 4,07 ± 0,03 to ensure that the wheel does not follow the same path all the time.
5.3 Swivel castor The swivel castor is shown in Figure 2. The wheel is made from a steel roller bearing. The diameter shall be (47 1) mm, the width shall be (20,6 0,5) mm. The travelling surface shall be cylindrical with chamfered edge with radius 1 mm. The castor can move freely about the swivel axis. The swivel axis shall be free to move vertically (which may be achieved with roller bearings at both ends of the axis, at least 300 mm apart) and shall be loaded so that the total load applied by the castor is either (150 5) N, (250 5) N, (350 5) N, (450 5) N or (550 5) N. The overhang shall be (19 1) mm, see Figure 2.
6 Preparation of test specimens
The resistance to rolling wheel is measured on at least 3 specimen made in accordance with EN 13892-1. Square slabs with minimum edge length of 350 mm and with a thickness of 30 mm shall be used as specimens Where the product is intended to be applied at a thickness less than 10 mm 3 test areas shall be made with the minimum thickness, but not less than 0,5 mm, and three test areas shall be made with the maximum thickness of the screed material as indicated by the manufacturer. When the thickness is less than 30 mm, the screed material should be applied onto a concrete substrate according to EN 13892-1.
BS EN 13892-7:2003 – Methods of test for screed materials — Part 7: Determination of wear resistance to rolling wheel of screed material with floor coverings