Temporary Bypass Road Pavement Optimization
Report
2-Year Design Life - Conceptual Engineering Assessment
1. Proposed Road Layer Configuration
Recommended temporary pavement section:
Layer
Thickness (mm)
Asphalt Wearing Course
40
Cement Treated Base (CTB)
150
Geotextile Separator
1 Layer
Compacted Existing Subgrade
Existing
Total Thickness
190
2. Structural Number (SN) Calculations
Conventional Pavement
SN = (3.94 x 0.44) + (7.87 x 0.14) + (11.81 x 0.11) = 4.13
Proposed Temporary Pavement
SN = (1.57 x 0.44) + (5.91 x 0.20) + 0.30 = 2.17
3. Strength and Cost Comparison
Parameter
Conventional
Proposed
Total Thickness
600 mm
190 mm
Structural Number
4.13
2.17
Design Life
20+ Years
2 Years
Subbase
300 mm
Not Required
Binder Course
60 mm
Not Required
Base Material
200 mm Granular
150 mm CTB
Material Volume
100%
30%
Estimated Cost
100%
50-65%
Estimated Saving
-
35-50%
4. Summary and Recommendation
The proposed pavement structure comprising 40 mm asphalt wearing course over 150 mm cement
treated base and geotextile reinforcement provides a practical and cost-effective solution for a
temporary bypass road with a service life of approximately two years. Compared with the
conventional 600 mm pavement section, the proposed design reduces thickness by approximately
68%, reduces imported aggregate quantities by approximately 70%, and can achieve estimated
cost savings of 35% to 50%. The solution is recommended only for temporary roads with controlled
traffic and adequate subgrade conditions. Final design should be verified against actual traffic
loading, CBR values, groundwater conditions, and project specifications.