FIELD: petroleum processing and polymer production. SUBSTANCE: storage-stable mixtures of bitumen and thermoplastic polymer are prepared as follows. Bitumen product, in which summary content of asphaltenes precipitated with n-heptane, those with n-pentane, and saturated paraffins divided by summary content of aromatics and tars gives value between 0.200 and 0.270, is brought into reaction with thermoplastic polymer for 15 to 120 min at 160-200 C observing bitumen-to-polymer weight ratio between 80:20 and 95:5. Resulting composition is diluted with bitumen or bitumen component, in which quotient as indicated above lies between 0.270 and 0.700, in amount providing concentration of polymer between 2.5 and 15 wt %. The latter mixture is heated to temperature 160-200 C for 30-90 min. EFFECT: improved rheological properties of bitumens and simplified their preparation procedure. 16 cl, 2 tbl, 7 ex
