Modified asphalt production from the hydrocarbon resin, SBS and LDPE

Modern highway transportation faces many challenges such as high traffic density, heavy load and high speed thus the asphalt pavements are founded to be subjected to various types of distress. That can be done by looking for good material to be added to the asphalt mix such as polymers LDPE, SBS and HR as shown by some researchers. The main objective of the work is to find new bitumen mix which is compatible with the Iraqi standard and saved the environment. The result indicates an improvement in most of the modified bitumen with HR, SBS and LDPE. 10% WCO, 88% bitumen and 2% HR give 60 mm Penetration, 99.3% solubility, 95 ductility, 44 C softening point and 288 flash point were seen to be optimum with the selected standard. At the end, the study indicates that a good quality bitumen can be achieved using HR, SBS and LDPE.


Introduction
Hot-Mix Asphalt (HMA) is the most commonly used paving material around the world. It's known by many different names: HMA, asphaltic concrete, bituminous concrete, plant mix, bituminous mix, and many others. HMA is a combination of two primary ingredients: asphalt binder and aggregates, whereas; aggregates include fine and coarse materials, typically a combination of different size rock and sand [1]. The aggregates total is approximately 95% of the total mixture weight. They are mixed with approximately 5% asphalt binder to produce HMA. The typical volume of HMA mixture is approximately 85% aggregate, 10% asphalt binder, and 5% air voids. To enhance the performance and workability of many HMA mixtures, additives are added in small amounts. Asphalt pavement is called flexible pavement because it is much more flexible than cement concrete pavement [2]. Asphalt pavement performance is affected by several factors, e.g., the properties of the components (binder, aggregate and additive) and the proportion of these components in the mix. The performance of asphalt mixtures can be improved with the utilization of various types of additives, these additives include: polymers, latex, fibers and many chemical additives [3,4]. It's proven that the addition of certain chemical or materials additive to asphalt mix can improve the performance of final mixture. The addition of polymers typically exhibit improved durability, greater resistance to permanent deformation in the form of rutting and thermal cracking. In addition, it increases stiffness and decreased fatigue damage. There are other additives that would enhance the life of the road pavement and also solve many environmental problems [5,6,7]. In order to improve the performance of asphalt pavements, many polymeric substances have been incorporated in asphalt mix as additives in many forms. Polymer modification of bitumen and asphalt mix offers several benefits. These include enhanced fatigue resistance, improved thermal cracking resistance, decrease in temperature susceptibility, and improve rutting resistance [7]. The aim of this work is to identify mixture characteristics and the efficiency of the asphalt binder designed using styrene-butadiene-styrene (SBS), low density polyethylene (LDPE) and hydrocarbon resins (HR) also studying the characterization of the modified bitumen to meet the Iraqi standard. asphaltenes and 32.4% resins was made from residual oil and was applied to enhance the viscosity, adhesion and temperature stability. Hydrocarbon resin, a kind of yellow particle, can be used to improve the viscosity and adhesion of the bitumen mixture. The bitumen used in the experiment was compatible with the Iraqi standards R9.

Bio-asphalt preparation:
The bio-asphalt was prepared by the definite procedures as follows: 1) The moisture degree of WCOR is 3%, so WCOR sample was uniformly heated to 170 o C firstly to remove moisture, but the maximum heating temperature should be less than 180 o C to avoid the composition loss and excessive oxidation.
2) Then, WCOR and HR was added heated to 170 O C and then stirred for 60 min at 400 rpm.
3) Finally, the temperature was reduced to 155 o C, then the LDPE were added (stirring for 50 min at 400 rpm to ensure the polymers swell adequately).   Table (3).

Effect on Penetration values with different Modifiers
The penetration values of bitumen modified with different percentage of SBS, HR and LDPE are shown in Figure (2 and 3).  proven by [9]. This may be inferred from the reduction in viscosity of binder with increase in modifier content.

Effect on Softening point at different binders
The softening point values of bitumen modified with different percentage of modifiers are given in Figures (4 and 5). All binders with LDPE matched with standard R9.

Effect on Ductility values
Effect of various percentages of modifiers with and without LDPE and SBS on ductility can be seen in both Figures (6 and 7).  Ductility value remain constant at HR percent higher than 6% as noticed from binder 3 to binder 10. The increase in ductility with HR was also approved by [8]. Figure (7) shows no effect of the LDPE and SBS on the ductility value.

Effect on flash point values
Effect of various percentages of modifiers on the flash point is shown in Figure ( The flash point value was decreased from 288 C for binder 1 to 263 for binder 10 were the sharp decrease was due to the increase in the HR from 2% to 20%. All the binders were not compatible with the R9 standard.

Effect on solubility
The solubility of the asphalt mix was studied within/ without LDPE as shown in Figures   (10 and 11). 10%. Also, any further increase in the HR percent has no effect on the solubility of the bitumen mix. Almost, all binders have close solubility value to the standard R9. Fig. (11)

Conclusion
The penetration values are slightly decrease significantly from 47 in binder 11 to 41 in binder 16. the softening point of modified bitumen increases steadily while Ductility value remain constant at HR percent higher than 6% as noticed from binder 3 to binder 10. The flash point value was decreased from 288 C for binder 1 to 263 for binder. Solubility value increase with the increase slightly of HR from 2% to 10%. All thementioned binders are all compatible with the Iraqi standard and these material are wieldy available in the plastic waste which make the bitumen mix cost efficient environmentally.