What are the latest innovations and trends in hot mix asphalt recycling equipment and technology?

1 RAP Preprocessing

Before RAP can be used in HMA recycling, it needs to be processed to remove any contaminants, such as dirt, metal, or glass, and to reduce its size and gradation. RAP preprocessing equipment, such as crushers, screens, and magnets, can help achieve these goals and prepare the RAP for mixing with new aggregates and binder. Some of the latest trends in RAP preprocessing equipment include using mobile or portable units that can be easily transported and operated at the project site, using sensors and automation to optimize the crushing and screening operations, and using water or air jets to clean the RAP and remove dust.

2 RAP Heating

One of the main challenges of HMA recycling is to heat the RAP to a suitable temperature for mixing with new materials, without damaging the aged binder or causing excessive emissions. RAP heating equipment, such as drum dryers, batch heaters, or infrared heaters, can provide different methods and levels of heating, depending on the type and amount of RAP, the desired recycling rate, and the environmental regulations. Some of the latest innovations in RAP heating equipment include using microwave or induction heating to selectively heat the RAP binder, using hot air or steam to heat the RAP in a closed system, and using recycled oil or gas as fuel sources.

4 RAP Storage

Once the recycled HMA mix is produced, it needs to be stored and transported to the paving site. RAP storage equipment, such as silos, bins, or trucks, can provide different capacities and features to store the mix without compromising its quality or performance. Some of the latest innovations in RAP storage equipment include using insulated or heated silos or bins to maintain the mix temperature and prevent segregation, using self-loading or self-unloading trucks to reduce the handling and loading time of the mix, and using GPS or RFID systems to track and manage the mix inventory and delivery.

5 RAP Paving

The final step of HMA recycling is to pave the recycled mix on the road surface. RAP paving equipment, such as pavers, rollers, or compactors, can provide different modes and methods of paving, depending on the mix design, the pavement structure, and the traffic conditions. Some of the latest trends in RAP paving equipment include using intelligent compaction (IC) systems to optimize the compaction process and ensure the density and uniformity of the pavement, using infrared or thermal cameras to monitor the temperature and moisture of the pavement, and using 3D paving or machine control systems to improve the accuracy and quality of the pavement.

6 RAP Testing

To ensure the quality and performance of the recycled HMA mix and pavement, it is essential to conduct various tests and evaluations throughout the recycling process. RAP testing equipment, such as laboratory or field devices, can provide different types and levels of testing, depending on the purpose, stage, and scope of the testing. Some of the latest innovations in RAP testing equipment include using non-destructive testing (NDT) methods, such as ground penetrating radar (GPR) or ultrasonic testing (UT), to assess the condition and properties of the existing pavement and RAP, using performance-based testing (PBT) methods, such as dynamic modulus or fatigue testing, to predict the long-term behavior and durability of the recycled mix and pavement, and using portable or mobile testing units to perform rapid and reliable testing at the project site.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?