<font color=blue>Sound guy. Your are quite correct in that you want to eliminate as many air voids as possible. What you need is incompressible material(rock) that fills voids with various sizes of diameter fitting in between the larger ones. And not a material that simply squeezes.
<font color=black>Very true. Using marshmellows was probably a bad choice of analogy for the situation... cerial would have been better. I was mainly trying to point out, as you did so eloquently, was the need to get rid of the air voids. Fines do that well.
Here in florida, we have so many different road construction process, it is hard to keep track of them all. For instance, in te county where I work, the county policy is no more slag roads out to bid by contractors, but that county road maint. crews can make them. Where as in say.. putnam county, the county is so poor, that their infrastructure is still mainly in place from the early 50's, and they are still using a large percentage of dirt roads, and roads constructed by the army corp. of eng's... heck.. they can hardly afford slag.. and regrading is just prolonging their eventual need for infrastructure improvements.
When we do DOT work sometimes, we use a metod called black base.
Esentially, you cut the subgrade into the native soil, and stabilize if necescary, then you lay a large lift of asphalt, instead of a subgrade material like limerock. The surface course and friction course of asphalt are applied as normal.
The cost for asphalt base is roughly the same as for a conventional limerock under asphalt road, with one exception. Time. A black base road can be cut and layed as you go, whereas conventional practices can take weeks.
We do many decel lanes as black base, and can do them usually in 1 day after prep is done.. saves bundles on maintenance of traffic.. and keeps the workers out of the drivers way.
Soundguy