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Paving Specifications

Paving Specifications

Paving Specifications

(OP)
I have an 800' driveway with a portion that reaches 16% grade. What is a good pavement thickness and number of courses to specify? I was told a 3/4" modified topcoat should be used, any comments?

RE: Paving Specifications

In the midwest we (where I used to work) found that it generally is necessary to use two courses of surface mix and use a total thickness of not less than 2-1/2".  Of course your base course should be firm and unyielding to the paver and truck traffic.

On the slope they may need to have a method for pulling the paver along, which can tear up your base course. My 500 ft.drive on a 10 percent slope in several parts has held up well over 10 years with 3-1/2" thickness.  6 inch base is crushed dolomite. Subgrade is low plasticity clay.

One slope is over 20 percent showing a little loss of fines due to chains on snow plowing equipment.

Don't ever make the mistake of "seal coating".  Most of them cause more cracking than if you omitted it.
 

RE: Paving Specifications

It depends, like oldest guy insinuates, on what's underneath.

However, I disagree on the seal coat comment.  I think one of the best ways to encapsulate volatiles and promote longevity in AC pavement is a seal coat of some sort.  Chip seal works the best, but an impermeable layer of some sort will maintain the pavement's design properties.

RE: Paving Specifications

What type of traffic is gonna be on your drvwy?

My drvwy is a little over 300FT, it is about the same slope.  I went with 4" of 5 sack concrete w/ no. 4 rebar on 18" cc VS. HMAC. But...we have very good low PI soils around here (no base course necessary)with little or no icing up. Concrete was more $, but it will last longer.
 

RE: Paving Specifications

Right now - concrete might be cheaper than asphalt.  In this area (nid-west) - many people are reverting to concrete because of cost and longevity

RE: Paving Specifications

If you're not going to have heavy traffic concrete may indeed be cheaper...

RE: Paving Specifications

Why not consider a cement stabilized base course - it should be cheaper than concrete and asphalt - especially if this is for a personal driveway.  Just add 4 to 5% pozzolan cement to a base course material, place and compact as soil. You can chip seal for the riding surface if you want.

RE: Paving Specifications

On the black paint "seal coat", my experience tells me it causes cracks, some eventually 1" wide with annual "painting".

Also, my checking of pavement conditions when looking to evaluate life usually shows the failure is deterioration at the cracks at the bottom.  That is where a good rubberized crack filler in routed joints will extend the life.

RE: Paving Specifications

Chip seal (with ss-1 tack) vs. "seal coat" with black paint are not equivalent.  The first is totally proven in hundreds of miles of asphalt highway maintenance, the second a cosmetic treatment for parking lots prior to striping.

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