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Automatic asphalt tester to reduce solvent usage

COLAS’s asphalt lab in Newcastle have commissioned a Pavelab50 automatic binder extraction unit for measuring the binder content and grading of its asphalt mixes. This is the first time that automatic solvent extraction testing equipment has been used for carrying out QC testing on asphalt in Australia. The used of the Pavelab50 equipment removes the need to carry out this test manually using the reflux method with solvent.

The use of Pavelab50 will reduce the demand for non-renewable solvents that are used for extracting bitumen from asphalt by recycling the solvent in the unit for immediate reuse. For a typical asphalt plant producing 100,000 tonnes of asphalt this amounts to a potential savings of 1,500 litres in solvent disposal per annum. The current manual solvent extraction test methods use about 5 litres of solvent per test whereas the Pavelab50 only consumes 0.5 litre of new solvent per test. The reduction in solvent consumption will reduce the need to handle and dispose of solvent which will have a positive impact on the environment.

Pavelab50 provides a safer work environment in the lab because the solvent is handled in a closed system thereby reducing the laboratory testers exposure to toxic fumes. It has a turnaround time of 75 minutes per binder extraction test which will free up the testers time to allow him to carry out other tasks. It will improve the accuracy of the binder content result because it will remove the human error in the manual test method.

The measurement of binder content and grading is a fundamental quality control measure which is mandated in specifications for testing of all asphalt mixes. This test has traditionally been carried out using solvent to extract the binder from the asphalt and is performed in a fume cupboard to limit the lab testers exposure to the solvent vapours. The automatic system allows the asphalt sample to be placed in the Pavelab50 unit to perform the solvent extraction in a closed system, so no fumes are generated. The solvent vapours in the Pavelab50 are cooled in a condenser so that the solvent can be recovered for reuse.

Published: Thu 20 June 2019