BS EN 12390:17:2019 pdf free.Testing hardened concrete.
The loading frame shall be sufficiently rigid to ensure uniform loading of the specimen(s) and capable of applying and maintaining the required load to within ± 3 % on the specimen or group of specimens for the duration of the test, irrespective of any change in the dimension of the specimen(s). NOTE 1 An example of a schematic diagram of a loading frame with 3 specimens operated by a hydraulic arrangement for the measurement of total or basic creep is given in Figure 2. Similar arrangements can also be used for a spring-loaded system in which only the system of loading will be different. Load shall be measured with a maximum permissible error of ± 2 %. The flatness tolerance for any plates or platens shall be 0,05 mm for the area in contact with the specimen. NOTE 2 For the purpose of this document, flatness can be assessed by the measurement of straightness in four positions (see EN 12390-1:2012. Annex B). A maximum of 3 specimens may be stacked for simultaneous loading in a single loading frame.The drying room or cabinet shall meet the following requirements. a) Air shall be circulated through the room or cabinet so that the same specified conditions are attained adjacent to all specimens under test. The air velocity should not exceed 0,5m/s near the specimens. b) The temperature in the room or cabinet shall be maintained at (20 ± 2) °C. c) The relative humidity in the room or cabinet shall have a target value of between 50 % and 70 % and maintained within ± 5 % of the target value. Other values may be used if allowed by national provisions valid in place of use. d) The temperature and relative humidity of the room or cabinet shall be monitored throughout the duration of the test and recorded at intervals not exceeding 24 h. Separate provisions may be required in the case of manual recording of data during laboratory closure periods. The drying room or cabinet shall be fitted with suitable racks for storing specimens. The racks shall permit free circulation of air around specimens, except for necessary supports, and shall be so situated with respect to the nearest wall or other obstruction that air circulation is not restricted in the intervening space. The horizontal supports shall consist of non-absorptive members having a total bearing width supporting the specimen of not more than 25 mm. BS EN 12390-17 pdf download.