Paul,
Whilst I agree with Eric Blond, if the pavement course below your dense
graded mix has been designed as a drainage layer then the waterproof membrane is
unnecessary. Drainage layers can be very effective design solutions.
[log in to unmask] wrote:
> Good Morning All
> Our Department of Transport in the Northern Territory, Australia has recently
> implemented the use of a waterproof membrane (usually a 10mm PMB seal) under all
> asphalt wearing surfaces used on our road network as there is a perceived
> problem of water penetrating the wearing course. Obviously this has increased
> our costs by 40-50% on new roads. Does anyone have any research they have
> carried out on the permeability of asphalt. I can understand the reason to use
> this under an open graded asphalt but it seems an ineffiecient and costly
> exercise under a dense graded mix.
> Regards
> Paul Bicknell
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