## 5 APT Loading and Evaluation of the 3 Different Seals Using the MMLS3
#### 5.1.3 A 20/7 mm Double Seal with a SASOBIT-M(r)  
Tack Coat and an  
Elastomer-(SBS)-Modified (S-E2) Second Application Followed by a Fog Spray  
Visual assessment: Figure 10 shows the surfacing of the double seal with and without testing with more than 18,000 repetitions applied at temperatures between 12 \({}^{\circ}\)C and 19 \({}^{\circ}\)C with the MMLS3. No visible difference between the test area and untested surfacing was detected. No sign of an excess of binder could be detected on any of the test sections, with no sign of bleeding of the binder. A 3D scan of the double chip seal surfacing with and without loading: The 3D scan images generated on the double seal are shown in Figure 11. Although a visual difference could not be detected by eye, the 3D scan images show a clear difference between the surfaces with and without loading. The height maps generated from the image are shown in Figure 12. The areas subjected to APT loading (left in Figures 11 and 12) clearly show a denser matrix when compared to the adjacent area where no loading was applied (right in Figures 11 and 12). It follows that the smaller 7 mm stone was packed closer into the first 20 mm seal under loading, leaving fewer gaps and moving towards a more densely packed, uniform surface. The volume and void ratios calculated from the scan data sets are given in Table 3. \begin{table}
\begin{tabular}{l c c} \hline \hline
**Parameter** & **APT Loading** & **No Loading** \\ \hline Solid volume (V\({}_{\text{T}}\)) (cm\({}^{3}\)) & 156.22 & 178.88 \\ \hline Sample area (cm\({}^{2}\)) & 100.2 & 100.2 \\ Largest height difference (mm) & 15.6 & 17.9 \\ Aggregate volume (V\({}_{\text{s}}\)) (cm\({}^{3}\)) & 84.83 & 110.40 \\ Void volume (V\({}_{\text{v}}\)) (cm\({}^{3}\)) & 71.39 & 68.48 \\ Void ratio (V\({}_{\text{v}}\)/V\({}_{\text{s}}\)) & 0.84 & 0.62 \\ Void ratio (V\({}_{\text{v}}\)/V\({}_{\text{T}}\)) & 0.46 & 0.38 \\ Mean texture depth (MTD) (mm) & 7.14 & 6.85 \\ \hline Mean profile depth (MPD) (mm) & 6.34 & 5.76 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Volume and void ratios calculated from a statistical analysis of the 3D scans of the single 20 mm seal shown in Figure 9.  
Figure 9: A 3D scan of the 20 mm single seal. Left: APT loading. Right: no loading. Figure 11: A 3D scan image of the area subjected to APT loading (left) and the adjacent area (right) that received no loading. Figure 12: Height maps obtained from the 3D scans of the area subjected to APT loading (left) and the adjacent section (right) that received no loading. Figure 10: Condition of the 20/7 double seal after APT at \(<\)20 \({}^{\circ}\)C.  
The area subjected to APT loading (left in Figure 12) illustrates the reorientation of the chips with less protruding features above the surface. The distribution of curvature shifts correspondingly towards lower values, i.e., uniformity. The roughness distribution indicates roughness values between 0.6 mm and 1.0 mm that is likely a representation of the surface roughness of the aggregates rather than macroscopic dimensions. 1.4 A 20 mm Cape Seal with 1.5% SASOBIT-M\({}^{\oplus}\)-Modified Tack Coat and an Anionic Nano-Silane-Modified Bitumen Emulsion Slurry without Any Cement/Lime Filler--First Test: 18,000 Repetitions Applied with the MMLS3 at Temperatures between 12 \({}^{\circ}\)C and 19 \({}^{\circ}\)C  
Visual assessment: Figure 13 shows the surfacings of the Cape seal subjected to loading. A slightly rougher surface could be detected in the test area, indicating that the 20 mm stone did not penetrate into the base but that the slurry actually filled any voids that was not properly filled during the placement of the slurry by hand. A 3D scan of the surfacing with and without loading: The height maps of the 20 mm Cape seal produced from the 3D scans are shown in Figure 14. The statistical evaluations of the data of the two data sets are given in Table 4. The 3D scans and the statistical analyses of the data confirm the visual observations.