How do I build a concrete driveway?

[304065]

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?

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

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?

4) Geotextile layer between subgrade and concrete?

5) Pitch, crown, etc?

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

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

8) What thickness?

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.

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.

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

[wdfifteen]

Where you live is an important consideration. In Ohio it can be just a 4" slab over 4" of #2 crushed limestone and pass code. If you want to get fancy and add wire mesh reinforcement. We don't put a vapor barrier down. Compacting the subgrade is very important.

[vash]

WD is correct.

getting the subgrade packed down is key! i seen them just pour down crushed rock over compacted soil. some simple rebar at 12" centers..and a simple mix.

as far as finishing. most folks just broom it. you stamp and color it, cost goes up.

i am farming out this job. i will do the survey, to set pitch..maybe pull up a special conc mix #from one of my state projects..and let the pros put it down.

[Porsche-O-Phile]

1. No, on grade is fine so long as you provide proper subgrade for drainage and support.

2. Slab type construction is fine, but make sure to include control joints (or Mother Nature will add them for you, probably where you dont want them).

3. WWF is fine - actual bar stock is (expensive) overkill. Make sure to support it above the substrate (don't just lie it on the substrate and pour on top of it).

4. Not necessary but don't think it would hurt anything either so long as it is moisture permeable (you don't want moisture to get trapped under the slab and freeze/thaw)

5. Slope 1/8" per foot min to edges and/or to bottom. Check your local codes just in case they require 1/4" or side collection swales, etc.

6. Anything is possible - finish, color, texture, pattern(s) up to you. Question of time/money - what do you want? I recommend standard float finish or rougher for traction. In a freezing climate you'd think broom finish might help prevent slipping but it just means snow/ice gets in the little grooves and it becomes a slick surface anyway. What do the local sidewalks have (hint-hint)

7. 4000 is fine

8. 4" typically fine.

9. Crushed stone topped by stone dust usually seems to work well. There are a number of ways to go. The important thing is keep it able to drain away any moisture.

Good luck!

[yellowline]

Pull up the specs of the autobahn. Probably a couple feet of subbase, then a foot-thick slab with #4 or 5 grid reinforcement.

That would be wicked expensive, but you would know it was done right.

[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. . .

[daepp]

No need for vapor barrier unless there will be enclosed living spaces above the slab.
No need to pay for 4000 psi unless big loads or big moisture.
#3 rebar 18" OCEW is very good to prevent cracking/separation - probably wont break the bank
No footings necessary
Good compaction of subgrade is a must

[A930Rocket]

I guess it depends where you live. I've always poured it right on grade using 2500 psi, 1x4 forms with no vapor barrier, rebar, WWM or fiber, but it's always been clay or sand. Tool joints 1/4 the depth, making no more than 100 SF sections and broom finish. Tool a joint at all places where concrete butts into a sidewalk/building at a 90* or you'll get a crack

We always calculate a yield of 65 SF per yard, so I come up with 83 yards for 5400 SF (unless my math is wrong again).

[Porsche-O-Phile]

Oh one other important thing to check is whether your town has a standard for the driveway-to-street apron. Lots of municipalities have standard details they'll provide for that condition and be sure you build it accordingly.

[A930Rocket]

Speaking of the driveway at the street, don't make a big radius at the street. The point will just break off. Tool a 45* so that if it does crack/break, you can replace one spot.

Originally Posted by Porsche-O-Phile

Oh one other important thing to check is whether your town has a standard for the driveway-to-street apron. Lots of municipalities have standard details they'll provide for that condition and be sure you build it accordingly.

[dondarnell]

Check the ACI standards