Quick question about concrete?

Question

am getting concrete poured next week to extend driveway, what do i need to do to prepare the area?I have it dug out and still have to put up edges so the concrete doesn't leave the area its needs to be, do i have to put anything else on ground before i get conncrete on it

Answer 1

i would put in type 1 or hardcore road stone and whack it down with a wacker plate, the concrete could crack as if it goes directly onto mud water can run below the concrete level and create hollows thus causing cracks

Answer 2

Yes. It should have a metal mesh suspended off of the ground on "chairs."

This makes it stronger and prevents it from cracking. Wet the edge of the old concrete first. If it is near freezing, don't pour, or add calcium chloride to the concrete. Give it 2 days before driving on it. It can be walked on sooner. 4" thick for sidewalk, 6" for driveway is best.

Answer 3

My advice as a concrete contractor is to cancel the mud because you are not near ready.



I don't say these things to be rude but look putting in concrete is pretty hard work and the concrete is not cheap. Do you really want to go through all this work again? Trying to do it on the fly is just asking for a project that looks like crap and will be a huge heavy reminder every time you see it that you should have waited. Even if it looks good when you finish it on the surface failure is lurking in the base if not done right and sooner than later it will fail, with a drive way it usually as soon a you drive on it.

Here are some things we do. Weither you are extending the sides or the front you need to "dowel" in to the existing slab with re-barb (just kidding) RE-BAR. these should be put every 18" on center. rent a hammer drill and drill the hole slightly smaller than the rebar about a good 10" into the existing slab the cut the steel about 2' long and pound it in the holes. You will tie your other steel to these. Then you will need to create a "matt" tying more steel (re-bar) every 18" it should look like big tic tat toe drawing. The steel should be everywhere the concrete is going to be right up to the forms but stay away from the edges about 2-3" all the way around. then the steel must be elevated off the ground with what are commonly called "dobies" these are little blocks of concrete about 3" square the goal is depending on how thick the slab is to have the steel in the middle to bottom 1/3 of the slab. Wire in my opinion is a little better than nothing at all for a driveway but steel is a hundred times better.

This is all done AFTER you have prepared the "base" because you could put the steel on 2" centers and it will still crack and move if the base it not proper. As the brick layer guy mentioned if it has been driven on you can get away with a topping of crushed stone. if not you need to remove more dirt and replace it with a good 3-4" of a "base-rock mix" that is used in your area. If this is a front of the drive way just flat as an approach you should make the front edge thicker than the rest of the slab by half and put a bar of steel in the "min footing" you created. if it is on the edge of the drive way its not really necessary. there are also the joints to worry about they must be placed in a manor that will allow the slab to crack in a controlled area, thats what they are for not just looks. if it is on the side of the drive make them in-line with the existing joints if there are none make them at least every 10' in every direction. if it is just an add on to the side (say 2' wide) just every 10'. For years we never used to use fiber in the mix but with todays concrete it is now standard for us concrete is just not like it used to be.

There are sooo many variables... you must make sure your forms a in nice and tight concrete is very heavy and once a form blows out its hell trying to fix it while the truck is there.

Over all my advice is make sure EVERYTHING is done and ready with out a doubt in your mind THEN order the concrete. Like I said before once it is in it is there to stay and it goes in much easier than it comes out. GOOD LUCK

Answer 4

Looks like you already have a lot of good advise. You may also consider leaving a permanent piece of lumber between your existing driveway and the new concrete for an expansion joint. It may be best to consult the person that will be finishing your concrete as none of us on line have seen the area you are working with.

Answer 5

Hi , I can only presume that you have all your levels right IE the fall off for the water and so fort. You do need to reinforce the concrete with steel as you have to make allowances to the weight of the vehicles travelling over it . Hardcore whacked to harden should be put in before any concrete as a suitable base

Answer 6

You're actually having cement poured which will form into concrete. You might put gravel in the bed and/or tamp down the ground before putting the gravel in. Some people reinforce it with wire but unless it's heavy duty, it may not be of much benefit.



Why not call the company that's coming out to pour it and ask them? I'm sure they'll give you some suggestions.

Answer 7

has this area been driven on for a while? if the base is solid you can pour on existing base. if it was me , i would put down a few inches of crushed stone. order the concrete with fiber and you wont need the mesh. mesh wont prevent cracking , it prevents heaving and separating if it does crack. besides the help usually just lets it lay on the bottom anyway. i would wait longer than 2 days to drive on it though. and what the heck is re-barb. if you are going to offer advice you should know something about the subject. its called re-bar.

Answer 8

Self leveler w/ ceramic!! Don t cheap out on it. PLUG ALL possible leaks and seal all around pips etc Leveler compound will flow out like water and go all over and depending on thickness ( up to an inch on most compounds) Plus a "stopper" board at end and doorways Use the recomended primer unless going directly over cement .You won t regret tiling over a leveling compound,and it will dry (depending on thickest part) in a matter of hours but overnite is recomended. MIX WELL w/ proper speed and time according to directions GL Add on DIY made a good point I assumed you d do... PROPERLY in stall cement board 1 st!!

Answer 9

You need to make sur e the ground is well compacted .

You need some concrete wire or fence to make sure your concrete doesn't crack, and you need a piece of "expansion" between the old and new concrete. Expansion is just a piece of asphalt-based fiber, that gives your concrete room to move and doesn't crack itself.

Answer 10

A couple of inches of gravel as a cushion would be good. remember that You must excavate a little deeper to allow for proper concrete thickness.

Answer 11

If you concrete straight onto mud, it will crack and sink. You need to put a 3 inch layer of rubble down and pack it down well.

Answer 12

quick answer not available ,,,not enough details !!!!!!!!!!

but 4500 pnd mud,with reinforcing fiberglass , wire mesh 3slump pour no looser 6'' if it's an apron this is not a side walk you'll be driving on it what part of the country how much of an extension,(expansion joints) ,, what are the current ground conditions in your area clay sand ect. not enough details email available

Answer 13

Just look at http://www.pavingexpert.com/concrete.htm for everything you need to know. Check other parts of this site for extra details.



If you can't follow the web site and have the ability to put it into practice, just go back to housework.

Answer 14

No I don't think so - just make sure area underneath is compacted to avoid any subsidence and cracking once dry.

Answer 15

if it a drive ..you need 150mm of hardcore ,,this need to be whacked ..then you will need 150 mm of concrete

Answer 16

i had drive laid 6yrs ago, no steel just a membrane, and its fine u can go ott

Answer 17

for some good advice go to PAVING EXPERT-AJ McCORMACK&SONit will tell you all you want to know

Answer 18

re-barb if you really want to reinforce it.

Answer 19

nope, you can concrete straight on to mud.