Budget constraints, rising bitumen cost, reduced of non-renewable material resources, growing traffic loads, increasing demand of asphalt and the desire to find more sustainable paving practices are forcing highway administrators to find methods for maximizing the re-use of Reclaimed Asphalt Pavement (RAP).
Over the past four decades most of the researchers have been focused on the development of procedures to recycle hot asphalt mixes content with up to 40% RAP, recently a few innovators of industry have tried to develop 70-100% recycling technologies to a level which production of 100% recycled mixes would be possible.
Parallel to that some studies were undertaken with an objective to investigate the concept of 70-100% recycling, determine whether such mixtures can perform as well as conventional asphalt mixes and the result could develop a mixture design method for 70-100% recycled asphalt.
Recycling in IRAN
The subject of operational use of Recycled Asphalt Pavement (RAP) in Iran has been limited to hot and cold in place and cold recycling. Other recycling method is hot recycling in plants. This method has a lot of potential for becoming pervasive in the country. So far Due to the lack of technology and machinery required, hot recycling in plants has unfortunately not been used in Iran. The advantages of this method include using high percentage of RAP (40% to 70%) and ability to control and quality of the production cycle.
Production stages of hot asphalt Recycling in plant with high percentage of RAP.
The recognizable steps in the production of hot asphalt recycling are:
- Optimal RAP management
- RAP crushing and grading(classification) process
- Identification important parameters of RAP
- Identification and selection of required additives and rejuvenator
- Preparation of asphalt Recycling mixture design
- Plant of Hot asphalt recycling process with high RAP percentage
- Quality control of recycled asphalt
