BS EN 13041:2011 pdf download – Soil improvers and growing media — Determination of physical properties — Dry bulk density, air volume, water volume, shrinkage value and total pore space
5.5 Ventilated drying oven set at (103 ± 2) °C.
5.6 Analytical balance with a scale interval of 0,1 g.
5.7 Shallow vessel, spoon or scoop approximately 50 ml capacity.
Prepare the laboratory sample in accordance with 8.4 of EN 13040:2007.
7.1 Moistening, saturating and equilibration at –50 cm water (–5 kPa) pressure head
7.1.1 Fill at least 2 tubes (see 5.2) with the test portion taking care to prevent artificial air voids. Cover each tube with synthetic gauze (see 220.127.116.11) secured with an elastic band. Place the tube on the grid in a dry water bath (see 5.3).
7.1.2 Slowly, with constant flow, fill the bath with water until the level reaches to within 1 cm below the top of the tube. Filling should take approximately 30 min.
7.1.3 If a tube shows signs of floating, place a weighted disc on the top of the tube allowing air to evacuate and at the same time ensuring that compaction of the sample does not take place, (see Figure A.4).
7.1.4 Allow to stand maintaining a constant water level until the sample is thoroughly wetted (up to 36 h).
7.1.5 Remove the tubes and without delay, transfer the tubes to the sand suction table. The bottom of the tube should be fully in contact with the sand. Apply a –50 cm water (–5 kPa) pressure head, measured from the bottom of the tube, for 48 h.
7.2 Filling tubes
7.2.1 Secure the gauze (see 18.104.22.168) with the collar (see 22.214.171.124) to the base of the lower sample ring (see 5.1.2). Attach and secure the upper sample ring (see 5.1.3) to the lower sample ring.
7.2.2 Empty the tubes containing the equilibrated (–50 cm water, –5 kPa) wet sample from 7.1.5 onto a clean surface and gently mix taking care not to cause any physical damage to the sample.
7.2.3 Transfer using the shallow vessel (see 5.7) approximately 50 ml portions of the mixed sample to the prepared sample rings taking care to avoid compaction or artificial air voids and filling the cylinder and removable ring completely.
7.2.4 Fill at least 4 units with the sample. Place the unit on the grid in a dry water bath. Slowly, with constant flow, fill the bath (see 5.3) with water until the level reaches to within 1 cm below the top of the tube. Filling should take approximately 30 min.
7.2.5 Maintain a constant water level for 24 h (see Figure A.5). NOTE Two different baths may be used, one for -10 cm water (–1 kPa) and one for –50 cm water (–5 kPa).
7.3 Suction –10 cm water (–1 kPa) pressure head
7.3.1 Carefully remove the units and without delay transfer to the sand bath (see 5.4) making sure there is contact between sand and the lower part of the unit. Cover the sand box and apply a –1 0 cm (–1 kPa) pressure head, measured from the middle of the lower ring.
7.3.2 It is important to regularly check that no air bubbles are present in the suction level regulator tubes. Apply the suction until equilibrium is reached. A minimum of 48 h and up to 72 h is required.
7.4 Separation of rings
7.4.1 Remove the double ring sample cylinders from the sand box and place on a flat solid surface. Carefully remove the upper ring in a vertical movement. Use a knife or straight edge to strike off the material level with the top of the sample ring without causing compaction. The levelling of fibrous materials can best be done by cutting off excess matter with a pair of scissors exercising considerable care to avoid other disturbances.
7.4.2 Remove any materials adhering to the outside of the sample ring and record the mass ( m 2 ) taking care not to turn the ring.
7.5 Optional suction –50 cm and –100 cm water (–5 kPa and – 10 kPa) pressure head NOTE After –10 cm water (–1 kPa) pressure head it is possible also to determine the air and water volume at –50 cm and –100 cm water (–5 kPa and –10 kPa) pressure head. The following procedure (see 7.5) can be skipped only if values for water and air volume at –10 cm water (–1 kPa) are necessary.
7.5.1 Carefully place the ring to the sand bath (see 5.4) making sure there is contact between the sand and the lower part of the ring. Cover the sand box and apply a –50 cm water (–5 kPa) pressure head, measured from the middle of the ring.