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Posted: Thu Mar 12, 2009 1:14 pm
by fingers
We have an unmade, unadopted road, shared by 15 properties. The road has been there 130 years and seems to be made up of compacted flint and earth. The threshold with the public road has started to develop serious pot holes in the braking and turn-in area. The threshold is not on public land.
Got three quotes for repairs using bitmac. Each contractor has proposed slightly different solutions. These differences are simply the area they think is best to fix. However, no mention has been made of digging out and adding a new base.
Is it okay to simply lay bitmac onto the existing flint & earth base?
Advice please.
Posted: Thu Mar 12, 2009 11:22 pm
by lutonlagerlout
you would be better with just a subbase and no bitmac than bitmac on top of earth
see main site for specs
LLL
Posted: Fri Mar 13, 2009 6:56 am
by Dave_L
What traffic uses this road? Refuse trucks etc?
As LLL has said, a sub base is essential - the depth required would depend on what is going to traffic over the surface.
I can see getting contributions from 15 households for this repair is going to be troublesome......
My advice is do the job once and do the job properly in this important area of the road.
Posted: Fri Mar 13, 2009 9:20 pm
by fingers
The road is a cul-de-sac and so there is no through traffic. Most traffic is cars (28 movements per day) , light goods (may be one per day) & refuse truck (once per week). Road is 7m wide with no pavements.
Totally agree with 15 household comments plus everyone has an idea, but hasn't really sought professional advice.
As an Enginner I agree with your last comment. I tempted to get a third party involved (eg a civil or a Qs) so I do not get it in the neck when it goes wrong.
Posted: Sat Mar 14, 2009 8:18 am
by Big Phil
as long as the receiving course is of sound condition then you should be ok (if it's stood the test of time for 130 years...), but i agree that you should get a 3rd party involved. core samples will measure the thickness of the existing 'subbase' and a lab will report on it's condition & constituents. a CBR or FWD will also help.
for the level of traffic volume the asphalt thickness would be minimal, as you just need to ensure waterproofing and provide an even, durable running surface. As opposed to a binder course/surface course, you could look for a one layer option? personally i'd go for a 20mm SMA, as it's more durable than laying a 20mm DBM as a one layer solution. maybe not as aesthetically pleasing as a smaller nominal size surface course, but a better engineering solution IMO.