POLYPROPYLENE-MODIFIED BITUMEN: RHEOLOGICAL AND PHYSICAL-MECHANICAL CHARACTERISTICS OF BINDERS AND ASPHALT CONCRETE MIXTURES

Abstract

The aim of this study was to evaluate the effects of isotactic polypropylene H-350 and sunflower foots (SF) on the empirical physical properties and short-term aging behavior of BND 100/130 road bitumen. The scientific novelty consists in the systematic experimental assessment of a locally sourced BND 100/130–PP H-350–SF system with simultaneous variation of PP and SF contents and blending technique, including evaluation of apparent phase heterogeneity and RTFOT behavior. Eleven formulations were prepared with 3–5 wt.% PP H-350 and 0–4 wt.% SF. Penetration at 25 °C, ring-and-ball softening point, and ductility were determined, while short-term aging of three formulations was evaluated using RTFOT. Penetration ranged from 31.4 to 76.4 × 0.1 mm, and softening point from 53.0 to 67.2 °C; phase-separated formulations showed paired values. RTFOT mass loss was 0.04–0.10%. For phase-matched samples, penetration retention was approximately 97.9% and 94.6% for the two reported phases of Mix 7 and 104.2% for Mix 9. An asphalt concrete test mixture prepared with a reported PP-modified binder showed water absorption of 2.95 vol.%, cohesion of 0.27 MPa, tensile crack resistance of 3.4 MPa at −10 °C, and compressive strengths of 3.1 MPa at 20 °C and 1.1 MPa at 50 °C. The results support empirical comparison of the formulations but do not establish EN 14023 compliance or Superpave Performance Grade. Further rheological, storage-stability, mixture-design, and statistical studies are required for definitive performance classification.