RUBBER CONTENT OF CRUMB RUBBER MODIFIED BITUMEN- SOXHLET METHOD

As per ASTM D6814, AASHTO M-320, AUSTROADS TEST METHOD AGPT/T142

TEST METHOD

This test method describes a procedure for measuring the particulate rubber content of crumb rubber modified binders. A crumb rubber binder sample is weighed and then subjected to continuous elution by solvent reflux using a Soxhlet extraction apparatus. The bitumen component along with process oils contained in the neat rubber are extracted, leaving the particulate rubber component retained in the Soxhlet extraction thimble. The recovered rubber is then dried, and its mass is determined to calculate the rubber content of the crumb rubber binder.

The set up consist :

1. Soxhlet extraction apparatus (including extractor, round bottom flask, and water-cooled condenser) which has an extractor with a nominal minimum siphoning volume of 100 mL, a round bottom flask with a nominal minimum volume of 500 mL and a water-cooled condenser with a nominal minimum length of 200 mm
2. Cellulose extraction thimble of suitable size to fit into the extractor of the Soxhlet extraction apparatus. An extraction thimble with a diameter of 33 mm, height of 100 mm and thickness of 1 mm (Pack of 25)
3. Heating mantle with thermostat control which is of suitable size to accommodate the round bottom flask.
4. Vacuum grease or silicone grease.
5. Beaker – with a capacity which is greater than the volume of the round bottom flask which has an internal diameter which is suitable for inserting the sieve into the top of the beaker.
6. Tweezers – to remove any boiling chips from the sieve.
7. 10cm dia Brass sieve : 75 micron
8. 10cm dia Brass frame - Lid-Pan

Additional Equipment required for the test (at extra cost)

1. Hot Air Oven
2. Electronic weighing Balance 100gm X 0.01 gm
3. Trichlorethylene : 500 ml
4. Fume Hood
5. Boiling chips. - 500gm
6. Cotton balls and lint-free tissue paper to make a Soxhlet extraction thimble plug.