Quantitative extraction and recovery of the binder method

The quantitative extraction and recovery of the binder method have been developed with the primary intention for use when the physical properties of the recovered binder are to be determined. 

It can also be used to determine the quantity of the soluble binder in the hot mix asphalt or reclaimed asphalt. The recovered aggregate may be used for sieve analysis or other aggregate testing. 

In fact, this method is a combined one-step procedure for extracting and recovering the binder from the bituminous mix. 

The binder extraction is carried out by washing the asphalt with solvent and filtering the solution, repeatedly in an extraction/filtration vessel. The extraction is carried out by rotating the vessel for 5 min at 30 rpm, while the vessel is positioned vertically (unlike the rotating bottle extraction method). The extraction vessel is equipped with three cloth sieves (2.00 cm, 300 mm and 75 mm). 

Each filtrate is distilled under vacuum in a rotary evaporator. After recovery of the final filtrate, the solution is concentrated to approximately 300 ml and centrifuged to remove fine mineral filler. The decanted solution is distilled under vacuum to remove the solvent. Nitrogen gas is introduced during the final phase of distillation to drive off any remaining traces of solvents. 

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More details on the quantitative extraction and recovery of the binder method are given in AASHTO T 319 (2008) or ASTM D 6847. However, ASTM D 6847 has been withdrawn in 2010. There is no replacement ever since probably because of the unpopularity of this test method. 

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