Crushed stone turnaround area

[shrews34]

I have the need to desing a crushed stone turnaround area for trucks. The soil is about average (2000 psf). The loading value for the trucks should be H20 loading. What would be a good thickness for the stone and what underlayment material should I use.

 

[cnstengineer]

The stability of the soil below your layer of crushed stone will need to be solid. I would recommend performing a proof roll of the subgrade prior to placing the stone. Make sure any fill placed to build the turnaround is properly compacted. I would also try to keep the stone thickness pretty beefy (10" - 12") if going to be used as a turnaround area by trucks, as the turning movements of the trucks could likely cause rutting in the stone. A layer of woven geotextile below the stone is an option for you also to keep the aggregate separated from the subbase and help distribute loading.

 

[cvg]

well graded aggregate base will be much more stable and would not require any underlayment unless you have a high water table or soft clay underneath.

 

[dirtsqueezer]

Sounds like you're on a budget with this one. Whatever you do, be sure to use CSTC on your upper layer and compact the HE!! out of it. (specify modified proctor and above 95% : 100% is possible!).

 

[casimmons]

Why not do a pavement design using the AASHTO method to calculate the required gravel thickness? You will need the CBR value, the ESALS (you can calculate knowing the number of trucks per day), as well as some other factors. Also make sure the owner knows that the gravel pavement will require periodic maintenance, regrading, etc. Especially since it is a turn-around area where some shoving of the gravel is likely.