Colvert???

[DVerbarg]

I am in the process of building a home with a 1300ft driveway and have two culverts. The secret to backfilling a culvert is to use material that packs extremely hard. When the material next to the culvert pipe is hard and will not "give" the culvert pipe cannot be flattened because the sides of the pipe are not able to "push out". Black dirt and clay do NOT pack well and will always result in flattened culverts if driven over with any weight or regularity. My front culvert only has 2 inches of fill on top and has had more than 20 semi trucks and fully loaded concrete trucks drive over it without flattening it. We used a limestone mix that the locals call "CA6" which is a mixture of small stone (1/2 inch and smaller) and fines. This CA6 packs like rock after a couple weeks, I learned this the hard way when I waited a couple weeks before doing a final grade on the driveway.

Hope this helps.

DavidV

 

[Harv]

DVerbarg -

Okay, now you've got my interest! I was still wondering what to use for backfill and it sounds like you have the answer. Not quite clear on the "packs like rock" part, though. You said you waited a couple of weeks before final grading and it was aleady hard. Was it driven on for those two weeks, or did it pack down all by itself? In other words, if I have a load of the stuff delivered, how long can it sit in a pile before I use it? Since I only make it up to the property 2 or 3 times a month, I don't know how long it will take to complete my culvert project.

Oh, yeah -- and is this stuff available from regular concrete suppliers, rock yards or where? And the usual question -- is it pricey?

 

[gordon]

In our area they call it CR6 it is also called crusher run and crush and run to name a few. It can be left in a pile for a long period of time but what happens after a few months the dust--crushed limestone-- will settle some leaving the larger gravel on top, but it won't pack so tight when in a pile that you can't work it. If you did put it down and it ended up rough and you did want to grade it again wet it down first if possible and it will work alot better and easier. Around here we use just the limestone dust for training tracks for the race horses. I just spread 80 tons of it last week for two circle drives the man was adding to his regular drive that I put in a few months ago. It turned out real nice its the first I used just the dust for a drive. One circle goes in front of the house the other circle goes back to his horse barn. Harv here is a link that might be useful to you http://www.rmcpacific.com/toolbox/tonnage.htm

Also something to think about is the lead in side of the culvert. Put stones around the pipe end to help detur (is that correct spelling) erosion and to channel water into pipe. Also a weedbloc fabric is a good idea behind the rock.
Gordon

 

[DVerbarg]

Harv,

It packs like rock when it is driven on and rained on. The water makes the "fines" wash down in and settle in. If it is not driven on it will pack but will take longer, depending on the amount of rain.

Our gravel came from a local gravel pit and cost about $75 for a 20 ton load. Prices vary by season and local demand. A 20 ton load would cover a typical 30ft x 12in culvert in a typical drainage ditch (what exactly is a typical ditch?) in this area. Many people do with only 15 tons. Check with your local gravel yard to see what cubic yardage you get from each ton of CA6 to properly plan your use.

Charges will vary by mileage and you may find it cheaper to use a 3rd party trucking firm instead of the gravel yard trucks. This is especially true when you are a distance from the gravel yard.

Hope this helps!

DavidV

 

[DVerbarg]

Harv,

Oh yeah, be sure to have the load dumped on the culvert. It will save much time (especially if you are still an aspiring Kubota owner).

David V

 

[DVerbarg]

Gordon,

Like that link for the tonnage calculator for gravel. Wish I had that when I was originally doing my driveway. That would have made my budget process much easier and saved much time.

David V

 

[Harv]

Wow!

You guys are a gold mine of information! Paul, you started this thread -- you getting all this?

I had done a fair amount of research on culverts, but I didn't come up with a fraction of the information you all have just posted. I dunno 'bout Paul, but I think I'm ready to start the culverts. /w3tcompact/icons/smile.gif

Thanks!

 

[gordon]

I wish I could get stone at those prices here is runs anywhere from $10-14 a ton+ trucking. Depending on time of year.
I use the calc. alot comes in handy I also have a concrete calc. http://www.improvenet.com/plan/calc/concrete_pop.html?shape=1&input1=20&input2=40&thick=4
gordon

 

[roysallis]

Bird,
Here in Alabama churt is red dirt/clay with rocks in it. The rocks are anywhere from marble size to grapefruit size. It is usually found in the hilly parts of the state. It is used for county roads, driveways, etc. because it will pack almost as hard as cement when it is wet down and compacted. Have you ever heard the song "Sweet Home Alabama" by the group "Alabama" that mentions churt rocks?

 

[Bird]

OK, I get the idea; just never heard the word before. I've heard the group, Alabama, lots of times, but don't remember that one.

Bird