Recycled Asphalt Pavement Base Course (also known as RAP for short) is an alternative material that offers a significant benefit to the environment without compromising quality of traditional base courses. During the remanufacturing process, the RAP is heated and mixed with other materials, reactivating the residual liquid asphalt to form a strong base course with properties similar to normal asphalt pavement.
Customers can purchase RAP Base Course premixed to place themselves, or alternatively, Boh Bros. can provide a full service. This includes milling the existing pavement, grading the recycled asphalt through a process known as fractionation, and finally blending it with other aggregates and anti-strip additives at Boh’s asphalt plant located in New Orleans. The alternative base course can then be placed by a conventional paver or equally as effectively with the same equipment used to install and compact traditional base course.
Within 30 minutes of placement, RAP Base Course can be opened to live traffic and performs much like a normal asphalt pavement. Unlike traditional base course, there is no need to wet, blade and shape, compact, and then apply the oil based curing membrane which takes up to 24 hours to cure prior to the placement of pavement. Additionally, 100% of the RAP Base Course material can be recycled for future use, giving it outstanding environmental credentials.
Profilers remove asphalt pavement that has exceeded its useful duration to prepare the area for a new surface. This old asphalt that was once destined for a landfill can now be recycled as RAP Base Course using Boh’s proven remanufacturing process. If you don’t have a site that requires profiling but still want to use RAP Base Course, don’t worry – Boh Bros. has extensive stockpiles that can be used.
With the latest technology and equipment, RAP is broken down to individual material sizes to create the same gradation requirements of traditional base course materials. Once the RAP is carefully graded through fractionation, the material is mixed through Boh Bros.’ asphalt plant, where it is reheated to a controlled temperature and blended to exact percentages with other additives to produce a product maximized for sustainability.
Using a technique known as warm mix processing, a small amount of water is introduced in the blending process to create a foam that increases the coating of the liquid asphalt onto the aggregates. This results in less energy consumption by the manufacturing plant and allows the RAP Base Course to remain at the adequate temperature for compaction for a longer period of time after placement.
Stringent quality control is undertaken from the time the RAP is received from the profiler until it leaves the site in the form of RAP Base Course and is compacted in place. Testing ensures that all three of these key steps are completed with consistency.
RAP Base Course can be placed in a high-volume capacity utilizing an asphalt paver or, in areas of limited access, with a bulldozer or motor grader. Immediately after placement, the product is compacted at the temperature set and monitored by a quality control technician. Once compaction is achieved and the product cools, the surface is fully functional, free of loose surface rocks, and ready for traffic on the same day it is placed.