Does this site need pavement? 1

[abih]

The site is in a very dry area (GWT>50 feet), and the clays on the surface have SPT N>30 by average. To use the site for plant traffic (18 wheelers for regular loading, no EASLs available), does the site even need a pavement? Can someone here share experience? Thanks.

 

[hokie66]

Probably only when it rains. If no traffic during wet weather, then it would just be called a hardstand. When it does rain, the clay will turn to mud.

 

[motorbiketocrank]

Generally speaking, yes you need a pavement.....unless you can guarantee traffic will only occur when there hasn't been any precipitation/moistening of the soil. Typical flexible pavement design for regular traffic loads over a lifetime is based on CBR.....which models the soil in a saturated condition. Your dense soil will have a higher CBR and therefore thinner pavement section than if you had a less dense/weaker soil...but some pavement section is still necessary. If you're in a region with freezing temperatures, freeze-thaw effects which lower the soil strength should also be taken into consideration.

 

[fattdad]

Asphalt or portland-cement type pavement is not necessary. Sure for a proper design, you'd need a CBR and some sense of how many trucks per day, which you could convert to some structural number requirement. And, yes, that CBR value would be based on the saturated properties of the compacted soil. There is no reason though you couldn't design a parking surface using dense-graded aggregate only. Some consideration on using drainage pipes may be helpful.

f-d

¡papá gordo ain’t no madre flaca!

 

[abih]

All right folks thanks for your input.

 

[cvg]

what are your criteria for requiring pavement?

dust control - yes it is probably needed
all weather - yes it is needed
reduce O&M costs for regrading every time it rains - yes it is needed
reduce capital expenditures at all costs - then don't bother

how much does it rain?
is the site grade flat or steep?
design traffic speed?

 

[racookpe1978]

You will get excess/continuous mud run-off when it does rain/snow/melt/sleet.

the "look" and professional of the site will be that of a perpetual (cheap) construction site.

 

[fattdad]

There are many staging areas for industrial buildings that are gravel. They accomodate heavy trucks and should be designed. They get rained on and maybe even some snow clearing. They require maintenance. I've known owners who want this. I've known owners who don't.

It gets down to managing client expectations. There is an engineering solution, however.

f-d

¡papá gordo ain’t no madre flaca!

 

[Ron]

Simple stabilization procedures will help if you do not want to go to the effort of a full pavement section. Asphalt emulsion can be combined with existing soil and a bit of graded aggregate to make a very stable, mixed in place pavement when properly compacted.

There are many other ways to do this as well, but yes, in my opinion you need some level of a pavement structure.

 

[cvg]

if you plan to go to the expense of throwing down gravel, than you will need to either stabilize the subgrade clays with cement or lime, or keep them dry. once they get wet, the gig is up and you will have heavy rutting and a big waste of money. not sure a chip seal is the way to go as it will not keep the water out very well and provides essentially no structural support.