Improved quality bitumen as a binder in flexible pavement through new additives and in-situ polymerization

Abstract

Bitumen is a visco-elastic material, which remains as residue after vacuum distillation of the crude oil. It is a complex mixture of organic compounds which cannot be tendency to degrade on exposure to heat, oxygen and UV light. These conditions generally lead to undesirable aging of bitumen and polymer degradation thus affecting the overall performance of SBS modified bitumen. Researchers are employing alternative materials such as scrap tires and waste plastics for bitumen modification. Large volumes of scrap tires and waste plastic are generated now a day’s causes environmental pollution which motivates the researchers to use these waste materials for bitumen modification. However, crumb rubber and waste plastic modified bitumen have some issues regarding storage stability as crumb rubber and plastic particles settles at the bottom of container which causes difficulty in transportation of these modified bitumen and therefore restricts their use for bitumen modification. classified exactly and therefore, their components are broadly grouped into asphaltenes and maltenes. The maltenes can be subdivided into saturates, aromatics, and resins. Asphaltenes are highly polar complex material of high molecular weight. Bitumen is extensively used for road constructions because of its excellent binding characteristics and low cost. However, increased stress on highways due to heavier loads, higher tire pressures and severe climatic conditions are causing premature failures, high temperature rutting, low temperature fatigue and stripping of road pavement. Various additives such as antistripping agent, reactive polymer, thermoplastic & thermo elastic polymer etc. a r e known to improve the performance of bituminous pavements. Out of these various additives styrene butadiene styrene (SBS) is generally used as thermo elastic polymers to improve elastic and rheological properties of bitumen and therefore, globally being used for bitumen modification in large volume. However, SBS modified bitumen shows some serious problems such as phase separation when stored at high temperature for long time and also have