Abstract
As a good asphalt modifier, natural asphalt has been the focus of more attention because of its low price and ability to improve the performance of modified asphalt. In this paper, the incorporation of a natural asphalt binder in the production of bituminous materials for pavement application in China was experimentally investigated to evaluate the feasibility of such a process and its potential benefits in terms of performance. For this purpose, an asphalt binder conventionally used in the south of China was blended with various percentages of a hard natural binder obtained from the region of Selenice in Albania. The content of Selenice natural bitumen (SNB) was 80.5%, having high molecular weight and the advantages of good stability and compatibility with virgin asphalt. The physical, rheological, and mechanical properties, as well as the modification mechanism of the binder and corresponding asphalt mixture, were evaluated in the laboratory. It was observed that the hard binder improved the response of the binder blend at high and intermediate temperature; this reflected a better stability, improved moisture susceptibility, and enhanced rutting resistance of the mixture. Fluorescence microscopy showed that after dissolving, the size of the SNB modifier became smaller and its distribution was uneven, presenting three forms, granular, agglomerated, and flocculent properties. Chemical test results showed that the modification mechanism of SNB was mainly related to the enhancement of hydrogen bonds and Van der Waals forces caused by sulfoxide and carbonyl along with the stress concentration caused by silica particles. Molecular composition revealed that the proportion of middle molecules has reduced while the proportion of large molecules has increased. It is considered that SNB is a promising low-priced natural modifier with excellent rutting resistance properties. Future research will be focused on the economic analysis, pavement life cycle assessment of SNB modified asphalt, and its application in perpetual pavements.
Highlights
Asphalt mixture is the most common material used for pavement applications
The possibility of incorporating Selenice natural bitumen (SNB), a natural harder asphalt binder, in the mix design of asphalt mixture was experimentally evaluated to benefit from the peculiar characteristics of such material
The investigation was initially devoted to determining the physical properties of the SNB material, and the conventional and rheological characteristics of binder blends prepared with a Pen 60/70 binder, an SBS modified binder and different contents of SNB
Summary
Asphalt mixture is the most common material used for pavement applications. Conventionally, this consists of a composite containing filler and aggregate bound together by a matrix of asphalt binder. In view of the increase in the use of high modulus asphalt mixture in pavement construction, there is a need for hard bitumen While different techniques such as blowing process or vacuum distillation and propane-precipitated asphalt [9] can be used to achieve the desired gradation, blending a soft binder with a natural binder additive represents an alternative option. The natural bitumen originating from the region of Selenice in Albania has found considerable application in different pavement-related constructions [14], to prepare hard asphalt binders to be used in the design of mixtures. This natural bitumen is commonly found in the cracks of rocks and presents a certain degree of impurity mainly consisting of fine particles. The existing literature has proved the feasibility of SNB modifier application, but there is a lack of in-depth research on the modification mechanism of SNB modified asphalt, as well as comprehensive and systematic research on the physical, conventional, chemical, rheological, and mechanical performance of both SNB modified asphalt and its corresponding mixture
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
