Answer :
To determine SNf (Structural Number of the final pavement structure), we'll follow the AASHTO 1993 Design Guide equations:
\[ SNf = SN1 + \Delta SN_{AC} + \Delta SN_{Base} \]
Where:
- \( SN1 \) is the Structural Number of the existing pavement,
- \( \Delta SN_{AC} \) is the increase in Structural Number due to the AC overlay, and
- \( \Delta SN_{Base} \) is the increase in Structural Number due to the improved base.
Given:
- \( SN1 = 0.44 \) (for 1.5 in AC + 6 in stabilized base)
- \( \Delta SN_{AC} = 0.36 \) (for an AC overlay with a1=0.44)
- \( \Delta SN_{Base} = 0 \) (assuming no change in the base)
\[ SNf = 0.44 + 0.36 + 0 = 0.8 \]
So, the Structural Number of the final pavement structure (\( SNf \)) is 0.8.
\[ SNf = SN1 + \Delta SN_{AC} + \Delta SN_{Base} \]
Where:
- \( SN1 \) is the Structural Number of the existing pavement,
- \( \Delta SN_{AC} \) is the increase in Structural Number due to the AC overlay, and
- \( \Delta SN_{Base} \) is the increase in Structural Number due to the improved base.
Given:
- \( SN1 = 0.44 \) (for 1.5 in AC + 6 in stabilized base)
- \( \Delta SN_{AC} = 0.36 \) (for an AC overlay with a1=0.44)
- \( \Delta SN_{Base} = 0 \) (assuming no change in the base)
\[ SNf = 0.44 + 0.36 + 0 = 0.8 \]
So, the Structural Number of the final pavement structure (\( SNf \)) is 0.8.