Study of the influence of the selenizza additive on the properties of road bitumen

Abstract

Natural bitumen is one of the oldest road construction materials. Currently, this material is used exclusively as an additive (modifier) introduced into petroleum bitumen to change its specific properties. Selenizza SLN 120 is one of the common natural bitumens used in various countries around the world. The aim of this study is to investigate the effect of adding Selenizza SLN 120 on the properties of road bitumen. To achieve this goal, binders with different concentrations of natural bitumen were produced, and the full range of their standard quality indicators was determined, with a focus on adhesive properties and changes in their quality indicators after aging by various methods. According to the experimentally obtained data, the addition of Selenizza SLN 120 to the initial bitumen is predicted to result in its modification, which manifests itself in a decrease in penetration at a temperature of 25°C, an increase in softening point temperature, an increase in brittle point temperature, and a decrease in ductility at 25°C. It has been established that with an increase in the amount of Selenizza SLN 120 in the initial bitumen, the temperature sensitivity of the binders remains almost unchanged, as evidenced by practically equal penetration index values in all binders. The modification of the original bitumen with natural bitumen Selenizza SLN 120 leads to a significant improvement of the adhesion of bitumen to glass surfaces - increasing the concentration of natural bitumen to 20% increases the adhesion index by 3.08 times. The results of the changes in the properties of bitumen binders modified with natural bitumen after aging are quite contradictory. On the one hand, an increase in the concentration of natural bitumen leads to an increase in residual penetration values, which may indicate less aging of the binder. On the other hand, an increase in the change in the softening point temperature, an increase in the brittle point temperature, and a decrease in adhesion indicate more intense aging of the modified binders compared to the initial bitumen. It has been established that more intensive aging is observed during the aging of binders by the RTFOT method, that is, the intensive contact of the entire volume of the binder with oxygen is a more significant factor than prolonged exposure to high process temperatures.