1、June 2008DEUTSCHE NORM English price group 9No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 91.100.15!$O b) petri dish
2、es or tins with lids; c) plastic sacks or bags with suitable closures; d) buckets with lids. NOTE 2 Long term storage of the test portion in a plastic sack or bag should be avoided. 5.3 Heat resistant stirrer, such as a knife, spatula or a shovel. 5.4 Balance, of suitable capacity, with an accuracy
3、of 0,1 % of the mass of the test portion. 5.5 Ventilated drying oven, thermostatically controlled to maintain a temperature of (110 5) C. NOTE 1 For temperature sensitive aggregates the drying temperature should be reduced to (40 5) C. NOTE 2 The air movements within the oven induced by a ventilatio
4、n system should not cause the loss of fine particles. 5.6 Desiccator with desiccant. As an alternative to the desiccator a closed cabinet containing desiccant may be used for the cooling stage. NOTE Silica gel with colour indicator and calcium chloride are suitable desiccants. 5.7 Tray(s), heat resi
5、stant and of sufficient size and number to suit the test portion. NOTE For small test portions, tins and watch glasses can be suitable. 6 Preparation of test portion The laboratory sample shall be reduced as specified in EN 932-2 to produce a test portion. Calculate the minimum mass of the test port
6、ion from the value of the upper (D) sieve size, in millimetres (see 3.1) as follows: - if D 1,0 mm, the minimum mass (in kilograms) shall be 0,2 D; - if D 8 mm the minimum test portion volume shall be 2,0 l; for D 8 mm the minimum test portion volume shall be 1,0 l. A.4 Cooling Instead of cooling th
7、e dried test portion to room temperature, weigh each tray and its contents immediately after removing it from the oven. NOTE It can be necessary to protect the balance from the heat of the tray. A cork mat can be suitable. DIN EN 1097-5:2008-06 EN 1097-5:2008 (E) 9 Annex B (informative) Example of c
8、alculation of the water content by drying in a ventilated oven Table B.1 Determination of the water content by drying in a ventilated oven (using one tray) 1 Container M2653,34 g 2 Mass of tray + moist test portion M1 + M23 574,4 g 3 Mass of tray + dry test portion Md1 + M23 389,7 g 4 Second weighin
9、g of tray and dry test portion Mdi+ M23 388,6 g 5 Difference of weighing data (line 3 - line 4) 1,1 g 6 (line 3 - line 4) x 100 (line 3 - line 1) 0,04 % (see note) 7 Mass of water (line 2 - line 4) (M1 + M2) - (M3 + M2) 185,8 g 8 Mass of dry test portion (line 4 - line 1) M32 735,2 g 9 Water content
10、 (line 7) x 100 (line 8) (mass %) 6,8 % NOTE In line 6, 0,04 % is less than 0,1 %. Additional weighing is not required and Mdibecomes M3because constant mass has been achieved. DIN EN 1097-5:2008-06 EN 1097-5:2008 (E) 10 Annex C (informative) Precision A precision exercise was carried out in 1988 in
11、 the United Kingdom involving 13 laboratories. The results of the exercise obtained by applying the oven dried method once to a single test portion were: Repeatability r1= 0,11 + 0,079 X where X is the mean value of the water content. Definitions of r1and X are given in EN 932-6. DIN EN 1097-5:2008-
12、06 EN 1097-5:2008 (E) 11 Bibliography 1 EN 932-6, Tests for general properties of aggregates - Part 6: Definitions of repeatability and reproducibility 2 ISO 6783:1982, Coarse aggregates for concrete - Determination of particle density and water absorption - Hydrostatic balance method 3 BS 812:Part 109:1990, Testing aggregates - Part 109: Methods for determination of moisture content DIN EN 1097-5:2008-06
