Highway Engineering

8.3 Rigid pavements,

8.3.1 Jointed concrete pavements (URC and JRC)

The Transport Research Laboratory publication RR87 (Mayhew & Harding,

1987) is, like LR1132, empirically based, taking account of full-scale concrete

road experiments. The document concentrates on performance data for jointed

unreinforced concrete (URC) and jointed reinforced concrete (JRC) slabs. The

sites evaluated had service lives of up to 30 years and were subject to traffic

loadings of over 30 million standard axles.

Mayhew and Harding derived two equations, each estimating pavement life

based on a set of independent variables.

For URC pavements:

(8.5)

where

Ln is the natural logarithm

Lis the cumulative traffic carried by the highway during its design life (msa)

His the slab thickness in mm

Sis the 28-day cube compressive strength of the pavement concrete in MPa

Mis the equivalent modulus of a uniform foundation providing identical slab

support to the actual foundation, measured in MPa

Fis the percentage of failed slabs

Definitions of failure in the slab include:

Ln Ln Ln Ln

Ln

LHS M

F

()= ()+ ()+ ()

+ ()-

5 094 3 466 0 4836

0 08718 40 78

...

..

242 Highway Engineering

225 mm granular

subbase

40 mm surface

250 mm CBM base

50 mm binder

100 mm base

250 mm lean-mix

roadbase

200 mm bituminous

surfacing

225 mm granular

subbase

HD 26/01 LR1132

Figure 8.9Comparison of HD 26/01 and LR1132 designs from Example 8.3.