An extn. arrangement (10) is used to determine the portion of binding agents and aggregates in a sample of asphalt. It incorporates a number of sieves (30,32) assembled into a sieve tower (12,14) which hold or take up samples, a sepn. unit (16) such as a centrifuge located down flow from the sieve tower, and a solvent recovery unit (20) linked both to the sepn. unit and the sieve tower. The sieve tower (12,14) is arranged as a unit as required, either in the sepn. unit (16) and the recovery unit (20) flow circuit, or in the flow circuit encompassing the drying assembly (24,26). USE/ADVANTAGE - The assembly determines the portion of binding agents and aggregates in a sample of asphalt. The arrangement minimises risk to human health by preventing the escape of solvents, and recovers solvents for reuse.