Based on the different analysis done on modified Gilsonite, a very large part of the budget of city development and construction companies is spent on binder and repairing asphalt roads. For that reason, perhaps the most important of them is economic. If asphalt can be produced with twice or three times the viability of conventional asphalt. There are significant savings on these costs. On the other hand, if the materials used in modified asphalt are cheaper. Naturally, the production cost of this material will also be lower. A second concern about the importance of using natural asphalt in gilsonite is the environmental issue. Petroleum bitumen contains heavy aromatic compounds that can be slowly absorbed in nature and result from environmental degradation such as rainfall using gilsonite and natural bitumen at its lowest cost has a noticeable effect on reducing this type of pollution.
- Improved driving conditions with this type of asphalt Improving driving conditions is another factor that makes the use of natural bitumen in road bitumen and asphalt very important. It is natural that if the roads have very high-quality modified asphalt. Driving on it will be easy and safe. This fact reduces indirect costs such as excess amounts due to accidents and decreases the value of the car. With low sensitivity to temperature changes, deformation and abrasion and water, natural bitumen-assisted asphalt can help improve road quality and improve driving safety on different roads and weather conditions. - Natural resource conservation with gilsonite asphalt Maintenance of natural resources is another important aspect of the use of gilsonite-modified asphalt. Every country needs to protect as much of its natural and mineral resources as possible. On the other hand, it should be noted that asphalt is made from organic raw materials. So, if the project is sustainable and recyclable; The outcome will be better in terms of natural resource conservation policy. For this reason, the development of improved asphalt with lower production costs, less toxicity and equal or better quality is the goal of asphalt researchers - Positive points of modified asphalt Laboratory results show that asphalt containing 10% gilsonite has a hardness of 1357 kg; In its absence, the said quantity is equal to 1097 kg.
Asphalt made with gilsonite therefore has higher hardness, resilience and effective life than normal asphalt, and in addition is cheaper and environmentally friendly and contains more bitumen. Usually 5-15% gilsonite is added to the bonding mix. This material reduces the low temperature properties of the pavement and makes it susceptible to heat cracking. Natural bitumen dissolved in hot asphalt reduces penetration and increases bond viscosity of modified asphalt. Permanent deformation in asphalt mix, also known as rutting, is one of the most important afflictions observed in asphalt pavements Rutting in asphalt mix layer is a permanent deformation of the asphalt layer near the surface. Since the binder phase is responsible for the viscous behavior of the mix, it plays a major role in determining many aspects of pavement performance such as resistance to permanent deformation This phenomenon is most important in the hot season during the first period of pavement life due to low stiffness of asphalt binder. Modifiers are added to the asphalt binder to strengthen the asphalt pavements against damage. Finite element methods provide data that cannot be obtained directly from experiments and are not easily accessible, such as information about the local stress and strain distribution of components in the aggregate structure A multiscale approach was developed and applied to investigate asphalt mix performance at multiple scales.
The viscoelastic properties of the moorings used in the analysis were obtained from the analysis of the rheological data obtained using the Dynamic Shear Rheometer (DSR) and consequently used to determine the viscoelastic properties of the mast scale. The reaction of the mastic scale was applied to the mortar scale. Finally, the response to the mortar scale provided input to the asphalt mixture scale. The results of this thesis prove the hypothesis that the elastic properties and viscous properties of binders affect the rut resistance of hot mix asphalt. It has been shown that mixtures with binders containing more viscous components (lower static strain) have lower static strain. It is also concluded that for binders with the same static stress under the same phase stress (same viscous component), the more elastic response of the bond leads to the lower static stress of the asphalt mixture. However, the effect of elastic component on rutting is small compared to the effect of viscous component of asphalt binder Regarding aggregate gradation, it was shown that a well-ordered intermediate gradation is capable of generating efficient particle networks at micro- and macro-scale, thus all scales of asphalt mixture but the bond stress level is reduced. Sorting of very fine aggregates could prevent efficient formation of the aggregate skeleton on a macro scale.
On the other hand, the use of coarser gradation leads to lower volume fractions of fine particles, prevents web formation and softer mastic mortar matrix shown that the asphalt mix composition changes continuously during repeated creep load testing. At the end of the secondary rutting zone, it is assumed that large deformations begin in the asphalt mix resulting in a deterioration of the aggregate structure This stage is the beginning of the tertiary zone of rutting. This study focuses on the effect of elastic component and viscous component of binder response on the rutting resistance of asphalt mixtures in primary and secondary zones where the mixture structure is not severely degraded due to the onset of large deformations. The result of this study clearly shows that blends with binders and more viscous components exhibit less permanent deformation. In such a case, the influence of the bond viscous properties on the rutting resistance of the asphalt mixture is considerably greater than its elastic response.