Aggregate Base and Subbase Lift 5

[CPENG78]

I came across a set of project specifications where it calls out for a relative compaction test to be done per CalTrans Test No. 216 with every lift of aggregate base and aggregate subbase. I did some research and this is what appears on the Table 6-1.11 of the Caltrans Construction Manual Section 6-109; at least as far as the test number to follow.

However I do not see anywhre in the project specifications, how much is a lift of aggregate. Anyone with experience on the subject, that can point to whether this is shown anywhere on CalTrans documentation?

What are typical lifts for aggregate base, subbase, asphalt pavement? thanks.

 

[Ron]

A typical lift, depending on the material, ranges from 6 to 12 inches. Clean sands and other non-cohesive, low fines materials are generally specified in the 12 inch lift range. Fine materials (clayey sand, silty sands) are generally specified in the 6-inch lift range.

It also depends on the compaction equipment. If the equipment is appropriate for the material, the above lift thicknesses can be increased.

 

[SirAl]

As usual, Ron provides good guidance. I would suggest that 6" lifts are OK with material upto 3/4" in size although you have to be careful with segregation as you lay out the larger sizes.

 

[BigH]

Typically have used 200 mm to 300 loose lifts.

 

[CPENG78]

Thank you everyone...I am assuming that the lift of material should have been specified in the project specs? or does anyone know where on Caltrans documents it is defined? From your posts, it sounds like it varies based on the type of material and I would imagine that recommendations from the project's geotech engineer would come in to play. Your thoughts...

 

[cvg]

maximum compacted thickness per lift is 6 inches per Caltrans Standard Specifications, Sections 25 and 26

 

[bimr]

Link to the Standard Specifications:

http://www.dot.ca.gov/ctjournal/images/2006_StdSpecs.pdf

 

[CPENG78]

As usual, everyone's imput has been of great assistance. Greatly appreciated.