Highway Engineering

Structural Design of Pavement Thickness 235

Cumulative traffic (msa)

Thickness of bound layers (mm)

0.01 1.0 100

100

200

400

300

Subgrade CBR = 5%

Subbase thickness = 225 mm

Probability of survival = 85%

Roadbase + Surfacing

Figure 8.3Design curve for highways with bituminous roadbase. (Crown copyright 1984)

Cumulative traffic (msa)

Thickness of bound layers (mm)

0.01 1.0 100

100

200

400

300

Subgrade CBR = 5%

Subbase thickness = 225 mm

Probability of survival = 85%

Roadbase

Surfacing

Figure 8.4Design curve for highways with wet-mix roadbase. (Crown copyright 1984)