Cement

[David Anderson]

I reading this thread with great interest.  I'm preparing to build a bus barn/shop and will be about 60' from the street.  I have the desire to pour the approach apron with concrete at the curb cut about 10' toward my property line then gravel/rock to the door of the barn.  I was thinking rock the size of railroad bed ballast which will alleviate dust as compared to crushed limestone. 

The city will accept a 10' approach, but I don't want to mess up the rock driveway and do it wrong. 

David

[boxcarOkie]

A better option may be a crushed concrete or what we call white rock in a 1 1/4 " size. The jagged edges of the rock interlock and make a good base. If you live in a wet area gravel won't support a bus. I'd charge you 2 cents for my opinion but then I'd feel guilty.... ps.... In our area they don't tear out the curb and repour the approach. They grind the concrete down.

My driveway and shop for that matter are 8" deep (set on rebar 18" on center) and the rock is spread out around the shop to a depth of 6" to 8" deep.  80% of my rock is recycled concrete that I get at a discounted rate (cheaper than crushed virgin stone) and it is holding up well.  The more you drive on it Scott, the more it packs it, after two years, it is about the consistency of cement, just a little bit loose on top. 

At first the bus would settle into it, and I would have to take a tractor to it and re-spread it, now I seldom do anything to it except occasional dress up a with a yard rake pulled behind a ATV.

Works for me.

BCO

[luvrbus]

All crushed rock base material have a binder (fines) of some type if you wash the crushed rock like they do for concrete mix it won't bind together and no way to bind river rock gravel except cement and sand then it becomes concrete.
Babell2 even concrete without calcium ( calcium will heat faster) if it gets hot in the truck will crumble later that load should have been sent back.
Calcium is not a good way to go hot water will do the same in cold weather but lots of plants don't have access to hot water so they add calcium I just was never allowed to use calcium in my concrete in the last 20 years.
David railroad's don't want the top 6 in of rock to bind the ties float I never built but one track and it cost me us not knowing what we were doing  lol  

good luck

[Lonnie time to go]

  Quality and strength also depend on how you order cement. 
The ratio of sand vs cement is the pound strength.
I agree that 6 inch concrete is needed over 4 inches.
Most  places ask what bag mix you want or what pound  standard is 3500#, go higher for a bus.
When you order it a concrete company should give info on best mix for your job.

Lonnie

[chev49]

Crushed concrete is a great base unless you get a load with some cut up aluminum pieces in it. then it's take the tire off the tractor time and head for Les Schwab.   Around here, which is north of eugene a bit, we have clay, and i've hauled in 54 loads of rock on my place just so i can drive on it.. and heavy equipment can still get stuck. If i was doing a truck pad, i would get out an 337 or so bobcat and scrape out about an extra foot or two deep.. add rock and use a small pavement roller  and get it real level, then build a reinforced 6 inch pad on top. I would also put in air, water, elect, sewer, etc close, as well as some places to hook to set in the concrete just in case i needed to use a comealong or portapower, etc.

[JohnEd]

Chev,

Being a "homie" you might just have put a stake in the heart of my little project.   I live at a lows point in the surrounding blocks.  Wifey was told that Monroe St, ours, was a creek bed in the very old days and the intersection of Monroe an 13th was the intersection of two different streams as 13th used to be a spur of Amazon Creek.  The surface soil is rock hard clay-like stuff and I think it was trucked in.  I recently installed new electric service and with that project I had to drive in 12 foot copper clad grounding rods.  I drove them at an angle under the house foundation as the water table here is really high,  in winter especially.  I put the pointy end down on the dirt which is 4 inches of gravel on top and leaned my 270 pounds onto the stake.  I pushed the thing into the ground FIVE FEET before I had to use the post driver the first time.  This must be a filled in lot and what is under it is wet sand.  We have a sump under the house that will start whenever we water the flower garden.  Curiously, I trucked in 3/4 minus and laid in 4 inches and that holds the 13,000 pound Winnie standing on those high flotation 19.5 X 8 Swampers.  Just to confuse me I guess.

I never intended to NOT involve a concrete contractor in this adventure but you guys have certainly opened my eyes.  I am smart enuf to not use river bed gravel or crushed river rock for anything but concrete but that is about the extent of my expertise.  This job may well work out to be to hard to do.

That tip about not breaking out the curb but instead grinding it down was  a gem.....if I can do that and if it is cheaper cause it sure sounds "greener".

Well, the plot thickens.  I'll make appointments on Monday to find out where I am.

Thank you all,


John

[chev49]

I was wondering just where your location was at, since Eugene and springfield has lotsa stuff like that. BTW, there can be other city/county problems there other than the inspectors which can be difficult.

I don't think you will have trouble building a pad as long as you prepare the ground properly. The neighbor adjoining my property to the west of me had to excavate 4' down and fill and compact the whole thing back to grade just to install a mobile on his 10 ac lot. Good thing he had all the equipment to do so.  I installed a mobile about 600' from his about three years ago, but i put rock on the spot and rolled it a lot, so that when the county showed up they thought it was great, and I didn't have to do anything except get the permits for the additional structure.. (I thought I might have to do what he did, so it was kinda a preemptive strike against that... and thank God, it worked)

Hope the city doesn't show up and say you gotta dig down several feet...I bet they will just let you put in a 6" pad. 

[luvrbus]

Chevy, they won't make you do that on a drive for building they do to remove the expansive clay called select fill some Wal/Marts I had to under cut as deep as 6 feet and fill back with select fill try that on a 240,000 sf pad LOL  most select material has to have PI of 10 or lower clay is in the high teens or 20's index

good luck

[boxcarOkie]

Chevy, they won't make you do that on a drive for building they do to remove the expansive clay called select fill some Wal/Marts I had to under cut as deep as 6 feet and fill back with select fill try that on a 240,000 sf pad LOL

good luck

My shop (50X70) took 18 loads of Oklahoma select for the pad.

BCO

[Lonnie time to go]

John
   You really don't need a contractor unless you just don't want to mess with it.
Pouring a slab is not to bad if you get some Friends together for a day of fun.

How you order the concrete is critical
     #3500 is basic strength
Not sure what the rating is for high strength concrete

Lonnie

[luvrbus]

John after this I will leave this post alone when pouring concrete don't let your contractor pour your slab with over a 2 1/2 slump on the concrete most flat work contractors like a 5 or 6 in slump so it will flow.
2 in slumps are hard to work but the concrete will be stronger, cures better won't crack as bad and last longer and don't let the contractor use a jitterbug to push the rock down and leave just the topping for a easy finish, adding water to concrete only weakens it pour it and make him cut the joints every 20 ft that should work in Eugene
The standard mix for 3000 lb concrete is a 141 lbs per yard or sack and a half as contractors call it but now most use 94 lbs of cement with 47 lbs of flyash.
I had my own batch plant and trucks for a few years till the big guys bought me out   


good luck

[robertglines1]

I didn't comment in you area because I'm not familur with you soil . In the midwest when we get real unstable soil we do lime or Kiln dust stablestation where we till dust into unstable soil to make it harden the sub soil so we can have a good foundation to put concrete upon.  sounds like your in good hands . I made a living with concrete for years had 4 pump trucks of my own. keep the slump down--3 or under-- they will bitch but you will have better job. on road work on slip form machines I ran 3/4 inch slump you could actually walk up the pile they dumped out of the placer in front of the slip form machine.  Amazing how much our board members have in common. Glad I'm concrete free in my retirement!!

[luvrbus]

Wow Bob I had 1 80ft Schwing that was enough for me lol if you kept four pumpers running no reason bus building is easy for you building a space shuttle is easier than keeping one going and about as cheap

good luck

[robertglines1]

The big pump had 150 ft of boom and could handle 3 mix trucks at hopper  lot of boom flex--you know what I mean.  4000 yard pours.  no more! done with that.   Ot I know   Life is good  just like a kid in a sand box!   Bob

[JohnEd]

Please don't anyone stop with the comments and advice now.  I got lots more opportunities to shoot the rest of my toes off with simple mistakes.

While I have poured and finished a couple hundred yards of concrete in my time, it was as a home owner or friend or relative.  I am bearing down hard on 70 (69 and counting) so I don't bear down anywhere as hard, if at all, as I used to.  Me doing any part of this project, beside grunting my support from a comfortable and cool seat, is no longer an option.  Wish it were different.

How can I tell what sort of prep and foundation I need for the gravel park area?  I think I need some sort of survey and I am going to assume that the concrete contractor will be wise to that.

When I get a read on the total cost and make a decision I will ask more pointed questions of this repository of wisdom that has never ceased to amaze me in its depth or breadth.  Thanks to you all.


John