Determination of flexible pavement with HBM base

In a composite pavement structure, the upper layer part is from asphalt and the lower part is from HBMs. 

For the choice of the surfacing and binder course on base with HBMs, all those mentioned in Sections 13.5.7.3 and 13.5.7.1 can be applied. 

The induced transverse cracks should be 3 m apart and must be aligned (maximum 100 mm tolerance) with any induced cracks in the underlying construction. The laying width of HBM is recommended to be not more than 4.75 m. The above minimise the possibility of having contraction or reflective cracks on the surface of the pavement in the transverse and longitudinal direction. 

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