Gravel compaction for parking and laydown area? 1

[StructureMan44]

My background is structural so please forgive the elementary nature of my question. Our contractor is looking to place gravel at 6" deep for a parking lot and 12” for an equipment laydown area. I assume these areas of gravel must be compacted. How much height will be lost due to compaction for both of these? When someone specifies a gravel depth (6” or 12” in this case) is it typically the uncompacted or compacted height? I imagine specifying a compacted or final height makes it difficult know exactly how much gravel depth should initially be placed.

 

[StructureMan44]

Basically, for 6" or 12" of compacted depth, how much uncompacted gravel depth must be brought to the site? 9"/16" or 10"/18"? Is there a general rule that can be used? This is for estimation and permitting purposes, not final design.

 

[cvg]

loose lift thickness depends on the shrinkage. shrinkage amount depends on the loose density, final compacted density as well as the gradation, particle shape and moisture content. You will not have any of those factors, so for estimating purposes, most road base is estimated and sold by the ton. estimate a density of say 125 pounds per cubic foot for the compacted gravel and you can get a reasonable number for the tonnage needed for the job. (You can probably get the maximum density of your gravel from the supplier or from the contractors QC testing)

 

[civilman72]

Unlike some material, properly graded gravel material has a low shrinkage/swell factor, so you will not find a significant difference between the compacted volume and placed volume. So to give you general quantities for an estimate, 7" of loose gravel will get you close to 6" of compacted gravel (assuming the material does not show up to the site bone dry).

 

[killswitchengage]

its easy , the given depth are those of the final stage . And don't worry gravel are competent materials and will not suffer much settlement due to compaction.