Applications

Application

The ReActive N50T application in RAP is one of the huge steps forward in asphalt recycling technology. The new generation of sophisticated rejuvenator, ReActive N50T, is specifically formulated to renew aged asphalt binder properties, enhancing performance and prolonging lifespan in RAP mixtures. This rejuvenator plays a critical role in the recycling of asphalt by enhancing its flexibility, adhesion, and general durability.

The application of ReActive N50T in the RAP mix seems very promising for the development of value-added performance in pavements with reclaimed materials since the demand for paving solutions that are sustainable and cost-effective has been on the increase.

Asphalt pavement recycling operations
Drum mix (A), Double Barrel-Drum mix (B) and Batch Plant (C,D)

Material preparation is the most important aspect of applying ReActive N50T in RAP mixtures. Materials are crushed and graded into the main desired grading curve along with the RAP. This ensures the material meets the specifications that ensure the best performance in the final asphalt. Proper grading and drying of the aggregates are key. These aggregates need to be thoroughly dried off to avoid probable moisture issues arising during the entire mixing process. Where there is moisture, problems such as steam generation during the time of mixing will arise, therefore probably interfering with the process of binder bonding with the aggregate. The percentage of RAP utilised in the mix can usually be within the range of 30% to 80% depending on what specifications the mix design should meet. Precise preparation ensures consistent distribution of ReActive N50T throughout the asphalt binder, enhancing the general performance and durability of the pavement.

Heating is one of the important processes to properly incorporate ReActive N50T into the asphalt binder. Aggregates are usually heated within a temperature range of 150°C to 160°C, while RAP is heated to approximately 160°C. This controlled manner of heating will prove highly instrumental in attaining proper mixing and ensuring that the rejuvenator is effectively incorporated with the oxidised asphalt binder. Should not be heated up indiscriminately, as such a process could trigger problems associated with the quick aging or deterioration of the asphalt binder. This could be very seriously compromising for the final pavement performance. Excess heating leads to the loss of a lot of important properties that are contained within the binder. On the other hand, too little heating results in an inadequate mixing/bonding of the rejuvenator. Proper temperature control can keep the rejuvenator effective during the whole mixing process, hence improving the final flexibility and performance of the asphalt mix.

ReActive N50T is added directly into the asphalt mixer during the production, using an automatic dosing system. Alternatively, it can be added directly in the bitumen storage tank. It is generally dosed between 3% and 5% based on the oxidised bitumen content. This dosage is quite critical for achieving the appropriate rejuvenation effect. Ensuring that the rejuvenators is thoroughly mixed into the binder is important to ensure homogeneity and, consequently, performance in asphalt mixtures. It is highly advisable to make use of a dosing pump in any plant application to ensure the exact measure and, therefore, integration of the rejuvenator within the mixture in a very constant way. Proper mixing increases the performance of the asphalt mixture in terms of flexibility and crack resistance. The homogeneous distribution of ReActive N50T enhances the binder’s properties and, consequently, results in improved pavement performance in terms of durability and resistance to environmental stresses.

The final step in the asphalt paving process is laying the asphalt mix at an optimal temperature that can attain sufficient density and evenness. Compaction is a critical issue in avoiding air voids within the pavement, which will significantly deteriorate its performance and service life. With effective compaction, the mix of asphalt will be tightly packed and evenly distributed, hence estimating the pavement to retain its structural integrity and resistance against deformation under the action of traffic loads. That is why it was densely packed and evenly distributed.
Workability enhanced by the addition of ReActive N50T enables more homogeneous compaction of the asphalt mix. This again is an indispensable prerequisite for the attainment of adequate pavement density, either to rut or to crack. Good practices of compaction, which include appropriate rollers and temperatures, are guarantees for qualitative and durable performances of asphalt pavements. Effective compaction enhances the resistance of the pavement to traffic and environmental stresses, hence ensuring a long-lasting and more reliable road surface.