2.1 Determination of angle of repose of fine-grained materials (size less than 10 mm): “tilting box test”. For use in laboratory or port of loading
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Statutory Documents - IMO Publications and Documents - International Codes - IMSBC Code – International Maritime Solid Bulk Cargoes Code – Resolution MSC.268(85) - Appendix 2 – Laboratory Test Procedures, Associated Apparatus and Standards - 2 Test procedures to determine the angle of repose and associated apparatus - 2.1 Determination of angle of repose of fine-grained materials (size less than 10 mm): “tilting box test”. For use in laboratory or port of loading

2.1 Determination of angle of repose of fine-grained materials (size less than 10 mm): “tilting box test”. For use in laboratory or port of loading

  2.1.1 Scope

The test provides for the determination of the angle of repose of fine-grained non-cohesive materials (size less than 10 mm). The results so obtained may be used when interpreting sections 5 and 6 of this Code for the materials in question.

  2.1.2 Definition

The angle of repose obtained by this test is the angle formed between the horizontal and the top of the testbox when the material in the box just begins to slide in bulk.

  2.1.3 Principle of test

When measuring the angle of repose by this method, the material surface should initially be level and parallel to the testbox base. The box is tilted without vibration and tilting is stopped when the product just begins to slide in bulk.

  2.1.4 Apparatus (see figure 2.1.4)

Apparatus is as follows:

  • .1 A framework, on top of which is attached an open box. Attachment of the box to the frame is by means of a shaft passing through bearings affixed to both the frame and the end of the box, enabling the box to be subjected to a controlled tilt.

  • .2 The dimensions of the box are 600 mm long, 400 mm wide and 200 mm high.

  • .3 To prevent sliding of the material along the bottom of the box during tilting, a tightly fitting grating (openings 30 mm x 30 mm x 25 mm) is placed on the bottom of the box before filling.

  • .4 Tilting of the box is effected by a hydraulic cylinder fitted between the frame and the bottom of the box. Other means may be used to obtain the required tilting but in all cases vibration must be eliminated.

  • .5 To pressurize the hydraulic cylinder, a hydropneumatic accumulator may be used, pressurized by air or gas at a pressure of about 5 kp/cm2.

  • .6 The rate of tilting should be approximately 0.3°/s.

  • .7 Range of tilt should be at least 50°.

  • .8 A protractor is fitted to the end of the shaft. One lever of the protractor is fitted so that it may be screw-adjusted to the horizontal.

  • .9 The protractor should measure the angle of the top of the box to the horizontal to within an accuracy of 0.5°.

  • .10 A spirit level or some other levelling device should be available to zero the protractor.

  2.1.5 Procedure

 The box is filled with the material to be tested by pouring it slowly and carefully from the lowest practical height into the box in order to obtain uniformity of loading.

 The excess material is scraped off with the aid of a straight edge, inclined at about 45° towards the direction of scraping.

 The tilting system is then activated and stopped when the material just begins to slide in bulk.

 The angle of the top of the box to the horizontal is measured by the protractor and recorded.

  2.1.6 Evaluation

 The angle of repose is calculated as the mean of three measurements and is reported to within half a degree.

  Notes: Preferably the test should be carried out with three independent samples.

  • Care should be taken to ensure that the shaft is adjusted to be horizontal before testing.

Parent topic: 2 Test procedures to determine the angle of repose and associated apparatus
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