Appendix C 1.5 Seal Design
A summary of the seal design for both lanes and the shoulder is provided in Table C 3.
Table C 3: Design calculations
| Attribute | Symbol | Units | Outside lane | Median lane | Shoulders |
|---|---|---|---|---|---|
| Traffic | – | AADT | 6000 | 6000 | See Table 5.2 |
| Design traffic | – | v/l/d | 1956 | 1044 | Adopt ≤ 100 |
| Basic voids factor | Vf | – | 0.15 (Figure 6.2) | 0.16 (Figure 6.2) | 0.21 (Figure 6.1) |
Adjustments: Aggregate shape Traffic effects Other | Va Vt – | L/m²/mm L/m²/mm L/m²/mm | Nil (Table 6.1) –0.04 (Table 6.2) Nil | Nil (Table 6.1) N/A (Table 6.2) Nil | Nil (Table 6.1) N/A (Table 6.2) Nil |
| Design voids factor Vf + Va + Vt | VF | L/m²/mm | 0.11 See Note 1 | 0.16 | 0.21 |
| ALD of aggregate | ALD | mm | 8.6 | 8.6 | 8.6 |
| Basic binder rate VF × ALD | Bb | L/m² | 0.11 × 8.6 = 0.95 | 0.16 × 8.6 = 1.38 | 0.21 × 8.6 = 1.81 |
| Binder factor | BF | - | 1.1 (Table 6.4) | 1.1 (Table 6.4) | 1.1 (Table 6.4) |
| Modified binder rate | Bbm | L/m² | 0.95 × 1.1 = 1.04 | 1.38 × 1.1 = 1.51 | 1.81 × 1.1 = 1.99 |
Allowances: Surface texture Binder Abs. by Agg. Binder Abs. by Pav. Embedment | Ast Aba Ap Ae | L/m² L/m² L/m² L/m² | + 0.1 (Table 6.3) Nil (Section 6.2.4) Nil (Section 6.2.4) Nil (Section 6.2.3) | + 0.4 (Table 6.3) Nil (Section 6.2.4) Nil (Section 6.2.4) Nil (Section 6.2.3) | + 0.5 (Table 6.3) Nil (Section 6.2.4) Nil (Section 6.2.4) Nil (Section 6.2.3) |
| Design binder rate Bbm + Ast + Aba + Ae | Bd | L/m² | 1.04 + 0.1 = 1.14 adopt 1.1 | 1.51 + 0.4 = 1.91 adopt 1.9 | 1.99 + 0.5 = 2.49 adopt 2.5 See Note 1 |
| Aggregate spread rate | – | m2/m3 | 900/ALD = 104.6 adopt 105 | 900/ALD = 104.6 adopt 105 | 900/ALD = 104.6 adopt 105 |
NOTES:
- Use of 2.5 L/m2 for the shoulder is considered to be an expensive option for a reseal and has a high risk of binder drainage in hot weather. Alternatives that may be considered include enrichment, or a small sized aggregate seal as this will provide a more economical and fit for purpose treatment.