[TimT]

When I am not being shill for Bill Rudtner, I am an engineer in real life, work in construction management on on some of the mammoth civil jobs in NYC....

I know many of you actually BUILD things for a living (unlike so many-paper-pushers here in the concrete jungle) so I thought I would ask-- if I were going to put in a concrete driveway, what design elements are necessary? I mean:

1) Do you need to pour footings like a foundation? Below the frost line?

NO

2) Or is it just a slab, like a garage floor?

Yes, thickness will depend on load


3) I assume you use rebar just like a garage floor and tie the rebar together. Does it just lay parallel to the direction of the driveway, or perpendicular, or does it form a box shape with the concrete placed around it?

Use wire mesh... again if heavy load perhaps rebar, just mesh for crack control

4) Geotextile layer between subgrade and concrete?

Depends on existing conditions, if you have a well draining stable sub-base no need for geo-textile seperation

5) Pitch, crown, etc?

Yes, again this will depend on existing profile/site conditions

6) Finish- broom finish, pressed to look like brick possible also?

Sky is the limit.... you can get colored concrete textured etc... a nice look is some lamp black in the mix, and a broom finish

7) What mix? I used 4000 pound for my barn floor and it fired off in about 2 hours.

NYS standard is 3000psi if you place the concrete in hot weather I would shy away from high strength mixes unless you can get curing water on the concrete as soon as finishing/initial set occurs

8) What thickness?

Again depends on loading... 4 in should be fine

9) I assume same kind of subgrade, I used 4" of #2 aggregate and compacted it down with a plate tamper before placing the vapor barrier. I understand that the better the subgrade the better the performance and longevity.

Yes, current practice on Federally funded FHWA projects is called 50 year pavement, 12" of subgrade, 4" of permeable base ("popcorn" 3/4 stone and cement, no fines) for drainage, 10" of PCC (Portland cement Concrete) reinforced depending on load, no need for any vapor barrier

A few rough calcs-- if the driveway is 4" thick, 12 feet wide and 450 feet long, that is 67 yards of concrete. And the subgrade is the same amount. At $100 per yard that is probably $7500 for the material with a 10% overrun.

Yes 67 yards. Considering concrete plants always short the loads, since they are batched by weight not volume.. you will need 7, 10 yard loads.. depending on the crew figure 15 minute spacing to allow for placement

Thanks in advance- this project is years away from being "shovel-ready" but I have started thinking, planning, budgeting. . .