A new approach to bituminous composites

Okuş, Dilek
The healing effects of fillers on bitumen have been known for many years. In this study, the effects of fillers, e.g. manganese dioxide, barium sulfate, perlite and vermiculite, and filler concentrations on morphological, mechanical, flow and sound insulation characteristics of bitumen were examined. It was also aimed to improve the mechanical and sound insulation properties of bituminous composites. Bituminous composites were prepared by using Brabender Plasti-Corder. Mixing was made at 130°C with 60 rpm for 20 minutes. 20/30 and 50/70 penetration grades bitumen, SBS polymer and CaO used in the composites were kept constant. While the amount of CaCO3 was decreased, other fillers (i.e., MnO2, BaSO4, perlite and vermiculite) were added in the same proportion to investigate their effects. According to the test results, all fillers were covered by bitumen as observed in SEM figures. MnO2 composites did not give good results in the tests and they were very brittle. While perlite seemed to have good mechanical properties, it was too viscous to be processed easily. Increase in the amount of vermiculite in the composite caused adverse effects on the rheological properties of composites. However, vermiculite composites provided a remarkable sound insulation in terms of the sound damping ratios. BaSO4 composites gave the best results in the mechanical, flow and sound insulation tests.