# Long-Term Monitoring of the Behavior of Modified Bitunens of RC Type
## 4 Experience with PmB RC
### Czech Republic
#### 4.3.3 RAP Requirements  
Allowing this higher dosage of RAP in the most widespread asphalt mixtures in the Czech Republic was preceded by the publication of the already mentioned standard CSN 73 6141 \"Requirements for the use of RAP in asphalt mixtures\" [45], which is related to and, in terms of national requirements, specifies and supplements the conditions set out in CSN EN 13108-8 ed. 2 [48]; in particular, it specifies the requirements for the procedures for the extraction, treatment, homogenization, storage, testing and control of RAP intended for use as a component construction material for the production of hot asphalt mixture. This standard describes, among other things, methods for the rejuvenation of aged bituminous binder in RAP and specifies requirements for newly produced asphalt mixtures in terms of demonstrating the effectiveness of the selected aged bituminous binder treatment method. This demonstration has to be carried out when more than 15% of RAP is dosed into the asphalt mixture. The standard specifies that when more than 15% of RAP is dosed into the asphalt mixture, the aged binder in the RAP must be treated during the production of the new asphalt mixture so that the basic parameters of the binder correspond to the parameters of the binder declared in the designation of the asphalt mixture. In the case of dosing a new non-modified binder, the RAP shall be treated by one or a combination of the following procedures:  
* Use of a rejuvenating additive in optimized quantities;
* Addition of a softer bituminous binder (gradation 70/100, 100/150 or 160/220) in an optimized quantity (however, the binder of the desired final gradation shall be indicated in the asphalt mixture designation). The polymer-modified bitumen type RC in accordance with CSN 65 7222-1 shall be used in the optimized quantity in the newly produced asphalt mixture with the new polymer-modified binder. Proof of the effectiveness of the selected rejuvenation method shall be carried out on the recovered binder at the frequencies prescribed by the standard. Both of the following shall be performed on the recovered binder:  
* Penetration test according to CSN EN 1426;
* Determination of the softening point according to CSN EN 1427. The requirements for the recovered binder of the asphalt mixture when using non-modified binder according to CSN EN 12591 [49] are given in Table 3.  
When there is evidence of the presence of polymer-modified bitumen in the RAP, the softening point temperature limitation above does not apply. The requirements for the recovered binder of the asphalt mixture when polymer-modified binder is used according to CSN EN 14023 [50] are given in Table 4. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Penetration of the Recovered** & **Softening Point of the** \\
**Desired Bituminous Binder** & **Binder at 25 \({}^{\circ}\)C According to** & **Recovered Binder According** \\  & **CSN EN 1426** & **to CSN EN 1427** \\  & **(0.1 mm)** & **(\({}^{\circ}\)C)** \\ \hline
50/70 & 30–55 & 48–60 \\
70/100 & 40–75 & 45–57 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Requirements for recovered binder from asphalt mixture when using non-modified binder according to CSN EN 12591. During the determination of the elastic recovery of modified bitumen according to CSN EN 13398, the test specimens shall be stretched to a length of at least 100 mm without breaking. In the case of the use of binder types not listed in the two tables above, the requirements for the recovered binder shall be determined by the investor. One of the first test sections in the Czech Republic using PmB RC was carried out in 2015. The actual implementation was a continuation of the research started in 2013 at Brno University of Technology in cooperation with OMV Czech Republic, s.r.o. In total, three asphalt mixture paving projects were carried out with PmB RC and RAP. Specifically, these were sections on roads II/602 Domasov (2015), III/42117 Lednice (2015) and II/461 Opava (2019).