The Brew Cabin

Dear Members of the Forum,

We are currently designing a tramway system embedded in a concrete sub-base finished with an interlocking concrete paver surface. I have come across details (mostly those from the US) which prescribe the use of geotextiles between an existing concrete sub-base and the bedding sand layer of the concrete paver surface. However they are more related to pavement overlaying on existing concrete surfaces, rather than paving on a newly built concrete sub-base. My intention is just to use the geotextile to prevent the migration of sand into any cracks or openings and hopefully prevent potential collapses on the paved surface. Do you agree with this application and what kind of geotextile would you recommend (I am hoping it will be a cheap one :)) ?

This is not a specification I've come across before, and I'd be more than happy to hear from anyone who has designed or constructed a similar pavement.

Assuming a reasonably tight finish is acheived with the concrete sub-base, I can't see that bedding sand migration would be a serious enough concern to warrant installation of a geotextile as a separtaion membrane. I could understand the use of a drainage composite in such a scenario, to prevent saturation of the bedding layer, and I wonder if that is what is meant in the US studies to which you refer.

Do you have any references I could check?

This is the IPCI spec that specifies geotextile use for pavement overlay on existing concrete or asphalt:
http://www.zaphers.com/cgi-bin/zs?icpi+specs+5

These are the ICPI details which show the use of geotextile (first one just the perimeter for pedestrian use and the second one on the whole width of the application for vehicular traffic -which is my case):
http://www.zaphers.com/cgi-bin/zs?icpi+ped+4
http://www.zaphers.com/cgi-bin/zs?icpi+vehic+2

The complete set of dwgs is at:
[url=http://www.zaphers.com/cgi-bin/zs?icpi

Again,]http://www.zaphers.com/cgi-bin/zs?icpi

Again,[/url] my intention is just to help keep the integrity of the sand layer, i.e. as you also mentioned to keep it from saturating with water and to keep it from draining away with that water. Somewhat like those sand-bags which people use to divert flood waters!

And these are for those who'd like to get more into pavement overlays, reflective cracks and the use of geotextiles, etc.:
http://www.usace.army.mil/inet....f

I'll have to read through those references as we do not rely on US standards in the UK and my experience is exclusively with British and European pavements. I'll read them this evening and comment later.

Why are you relying on US references? Are you not based in the UK/RoI?