AS 1012.13:2015 pdf free

AS 1012.13:2015 pdf free.Methods of testing concrete
A drying chamber with suitably controlled temperature, humidity and air circulation shall be provided for storing specimens in air and in which they can be measured in accordance with the following requirements:
(a) Air shall be circulated through the chamber in a uniform manner so that the specified conditions are attained adjacent to all specimens under test.
(b) The temperature in the chamber shall be maintained at 23±1°C for 90% of each 24 h period, at all times remaining within the range 23±2°C.
(c) The relative humidity in the drying chamber shall be maintained at 50 ±5% at all times.
(d) The temperatures and relative humidities shall be recorded at all times by a recording device which is capable of rapid response to changes in chamber conditions.The recording detectors shall be calibrated annually against a standardized A ssmann hygrometer or reference device.
NOTES:
1 A suitable rapid response device for recording temperature and humidity uses a combined detector with a thin-film capacitor for humidity and a platinum resistance thermocouple for temperature measurement. Response time for this type of detector is measured in seconds, and is virtually instantaneous within the narrow range required for this test method.
(e) The rate of air movement in the chamber shall be such that the rate of evaporation is 12±5 mL per 24 h, with a minimum value of 7 mL per 24 h. The evaporation rates shall be determined by measuring the loss in weight of water in 400 mL low-form beakers of internal diameter 78±5 mm, initially containing approximately 375 g of water at a temperature of 23±2°C. The weight of water in the beaker shall not fall below 325 g. Each beaker shall be placed midway between test specimens on the storage racks with the water level at approximately the same height as the top of the specimens. Systematic checks on the evaporation rates shall be carried out by varying the location of the beakers within the chamber at least monthly or where conditions have changed and the results duly recorded.
NOTE: The rate of evaporation should be maintained as close to 12 mL per 24 h as possible.
(f) The requirements for temperature, humidity and evaporation rate apply to each storage position.Positions which do not comply shall not be used for storage of test specimens.
(g) The chamber shall be fitted with suitable racks for storing specimens. The racks shall provide 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. All storage positions shall be kept occupied at all times, with dummy specimens if necessary.AS 1012.13 pdf free download.