# An Evaluation of the Efficiency of Compartmented
## Materials and Methods
### Porous Asphalt Mastic Mix Design and Mixing Procedure  
In an effort to evaluate the efficiency of the rejuvenator encapsulated in compartmented calcium alginate fibres, a Porous Asphalt (PA) mix was designed. The grading envelope Rationalisatie en Automatisering Grond-, Water- en Wegenbouw (RAW) 2005 was used to produce a PA asphalt mix typical of those used for road design i [18; 19]. The limestone used originated from a quarry in Norway, the filler material was hydrated lime (Wigro 60K), and pen 70/100 of bitumen was used. Figure 1 illustrates the mix grading curve and illustrates how the mix compares well with the grading envelope. The figure also shows the slightly higher passing of fine material than was required by the grading limits, but because of the high dust content of the aggregate, it was impossible to achieve a 100% match. Further consultations with industrial partners confirmed that the fit employed in this study compared favourably with PA mix production. Table 1 summarises these mix constituents and shows their proportions in the mix, both with and without fibres. The fibres were added in an amount of 5%, which in the total mix volume represents 0.23%. [PERSON] et al. [15] demonstrated that 5% is an optimum fibre content within an asphalt mix; mixes with a higher fibre content (10%) experience lower stiffness and strength values and have a lower healing efficiency. The aggregate mix constituent content was unchanged with the addition of fibres into the mix because the fibre is an active replacement for the bitumen and is not load carrying. Therefore, the fibre was inserted as a binder replacement.  
The porous asphalt mix was prepared using a 5l Hobart mixer. Prior to mixing, all mix constituents were preheated to 160 \({}^{\circ}\)C for 2 h. During the mixing process, sand, filler, and bitumen were mixed first, and fibres were then added gradually to the mix to avoid a conglomeration of fibres within the mix. The addition of the fibres resulted in a prolonged mixing period, which caused the mix to cool down and reduced its workability. Therefore, the mix had to be reheated to 160 \({}^{\circ}\)C several times during the mixing process. The final mixing was performed by hand, to ensure that the mix constituents (sand, filler, and fibres) were fully and evenly coated in bitumen.  
In order to account for the asphalt ageing, an aging programme was developed. The recommended by [PERSON] et al. [21], as follows: Long term; 15 years field ageing 4 h at 135 \({}^{\circ}\)C followed by 4 days at 85 \({}^{\circ}\)C in a forced air draft oven.  
Recently, [PERSON] et al. [12] and [PERSON] et al. [14] successfully used similar protocols to investigate the effect of short and long term aging of the asphalt mix containing alginate capsules and microcapsules encapsulating asphalt binder rejuvenator.  
Following the asphalt aging procedure, the mix was preheated to the standard asphalt mixing/compaction temperature of 160 \({}^{\circ}\)C and the fibres were gradually added to the mix to avoid conglomeration of the fibres within the mix. After the fibres were included in the mix, the test  
\begin{table}
\begin{tabular}{c c c} \hline \multirow{2}{*}{**Mix Constituent**} & \multicolumn{2}{c}{**\% Content in Mix**} \\ \cline{2-3}  & **without Fibres** & **5\% Fibres** \\ \hline
22.4 mm & 20.1 & 20.1 \\
16.0 mm & 25.6 & 25.6 \\
11.2 mm & 34.8 & 34.8 \\
8.0 mm & 7.4 & 7.4 \\
6.0 mm & 6.7 & 6.7 \\ Sand (2.0 mm) & 0.5 & 0.5 \\ Filler (\(<\)0.063 mm) & 0.5 & 0.5 \\ Bitumen & 4.5 & 4.3 \\ Fibre & 0 & 0.23 \\ \hline \end{tabular}
\end{table}
Table 1: PA mix design (percentage constituent content is given by weight).  
Figure 1: Porous asphalt mix grading, grading envelope RAW 2005 [20].  
specimens were prepared. The air void content in the mix design was 20%, with a target density of 2.05124 kg/cm\({}^{3}\) for the control mix and 2.05088 kg/cm\({}^{3}\) for the mix containing the fibres.