# Using steel scrap in place of rebar/mesh in concrete pads



## ghidley (Jul 26, 2008)

Is it acceptable to use/bury clean steel scrap in a concrete pad? I am creating a 24x20 outdoor pad for my tractor and implements and have some 3x6 foot flat framing made of 2x2 inch angle iron welded together in a grid. There is plenty of spacing for concrete to flow through. Common sense seems to indicate this would only help reinforce the pad. Pad is 6 inches deep with 1 foot deep 12 inch wide footers all around (floating pad).

thanks
greg


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## concretemasonry (Oct 10, 2006)

Flat steel is poor in concrete, because the smooth face limits the bond to the concrete. The size and smooth surface will limit the amount it reinforces the slab. If you do not have the bond, it just becomes something in the way preventing the concrete from acting as a unit and distributing the loads. You can expect some larger cracks in the concrete. A 4" slab with proper reinforcing steel would probably be stronger that what you propose.

Rebar is made to provide the most area and bond for the weight of steel. If smooth steel is used instead of the deformed you just need more tons of steel. Nothing beats smaller rebar at close spacing compared to larger bars further apart.

Sell the frames for scrap.


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## newpaint (Jul 25, 2008)

*Not a Professional*

I am by no means a pro, but I remember my dad throwing any piece of metal he could find in to the forms before the pour began. Nails, rebar, wire, angle iron, all of it. I don't think that you could get hurt being as the pad is 6" thick, it should fully cover all of your material and still have its full strength. I might put this stuff in alongside the traditional rebar and or wire mesh rather than instead of it.


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## Termite (Apr 13, 2008)

Although I see where you're coming from, this is not a good idea. Concretemasonry said it right. Rebar is formed in a way that gives the concrete something to grab on to, as the rebar and the steel and the concrete do not actually bond to each other. Smoother faces of metal will not give the concrete anything to grab to, and 2x2 angle iron will only create a weakened spot and a crack point. 

If you're ever around heavy concrete construction that incorporates imbedment of steel pilings and beams (bridge abutments, etc), you'll notice a heck of a lot of reinforecement around that steel...Partially because of the loads those pieces transmit, and partially because they create weak spots.


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## ididit (Jan 31, 2008)

While i dont think putting this junk iron in your slab will create any major problems nor a safty conceren sense its just a slab for equipment i agree with others here. Buy a roll of rewire ( the 6x6" mesh wire made for slabs) and cover the area with that. Pour the concrete making sure the wire is pulled up off the ground but does not show. Like concretemason said a proper 4" slab will probably be stronger the you 6" junk iron slab. The money you save on 2" of concrete may be enough to buy the wire. Unless you have very heavy equip. like 10 tons you dont need the rebar the wire is enough. If still in dought up grade to 3500# crete and/or fiber reenforced.
Besides 2x2 angle is very valuable, i would never just burry it. I cut it apart and use for something else.
That all being said i have used old chain link fence in a slab but it was just a small non load bearing dog pen of something like that.


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## ghidley (Jul 26, 2008)

Thanks to all of you for your advice. This is a very useful forum. I will use rebar in the footers surrounding the slab connected to wire mesh that will cover the slab area. Max weight on the slab is a 6,000 tractor and a 1,500lb backhoe attachment so I am not worried about structural support ... but I don't want the slab to crack in any significant way either so I'll follow your advice. This is all sitting on a few inches of gravel on top of well compacted DG.

thanks again!
greg


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## ididit (Jan 31, 2008)

You should be fine. Glad we could help. One more thing you proly already know- all concrete cracks it a given. Using the advice we gave will minimize it and keep it from falling apart. If your concered with what it looks like you can put in expansion joints. I know youve saw them before in large slabs. They can be done wet or sawed in later. The inevitable cracks will follow these straigt lines and not look bad.


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## Termite (Apr 13, 2008)

ididit said:


> You should be fine. Glad we could help. One more thing you proly already know- all concrete cracks it a given. Using the advice we gave will minimize it and keep it from falling apart. If your concered with what it looks like you can put in expansion joints. I know youve saw them before in large slabs. They can be done wet or sawed in later. The inevitable cracks will follow these straigt lines and not look bad.


Great advice!


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## yesitsconcrete (May 11, 2008)

baloney !!! what's w/this ' all concrete cracks ' horse-puckey ??? the oldest engineer'd building mtl in the world yet everyone still thinks it MUST crk,,, if its placed correctly & the jnts're installed right, there'll be no random cracking at all,,, trouble is everyone thinks conc's a piece of cake & excuses sloppy work by saying there's 2 kinds of conc - cracked & waiting to crk,,, just not so !!!

any crk that follows sawcuts is there BECAUSE the cut was made,,, they're call'd ' control ' or ' contraction jnts,,, expansion jnts serve an entirely different purpose to arch/engineers/contractors/educated owners,,, ' done wet or sawed in later ' works but ' later ', inevitably, leads to random crks,,, thank goodness no one mentioned ' isolation ' jnts or sealing of any jnt.

this topic of crack'd conc's becoming very tedious :whistling2:


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## ididit (Jan 31, 2008)

Well escuse the hell out of me mr. professioal!! Its just a tractor shed for damn sake and the op got his question answerd. If it was a $40,000,000 bridge i'd keep my mouth shut!! Then again he wouldn't have asked for help online either.


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## Termite (Apr 13, 2008)

I've heard that "my concrete doesn't crack" story out of dozens of concrete finishers. :no: 

The fact is that concrete does crack. The cracks may be microscopic and of little consequence, but they're there. Reinforcement is placed to keep concrete static _when_ it cracks, not _if _it cracks. Joints are placed or cut to control those cracks, and to make them occur where they're least problematic.

None of that means that big open cracks are acceptable to most of us, because properly placed and properly reinforced concrete on properly prepared subgrade won't have visible cracks. Cracked and crumbled concrete is of no value to anyone. Concrete with controlled cracking retains all of the properties that make concrete a valuable building material.

Sorry, but after four years of college education that centered around concrete, and after a number of years in the industry, I'm taking anyone who says that their concrete doesn't crack with a grain of salt.


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## yesitsconcrete (May 11, 2008)

' microcracking ' is another issue,,, bear in mind my experience 1st was dot, faa, & other fed work before commercial/residential/industrial,,, IF our work crk'd randomly, out it came & got replac'd - at our expense,,, termite's right in general - reinforcement in slabs-on-grade're generally to add strength during cure stress ( tension ),,, after the conc hardens, it holds the broken pieces together - not always successfully as, many times, those random crks become ' working jnts ' leading to spalling.

if this means your cutting crew ( man ) stays til oh-dark-thirty to get it done right, that's part of the job,,, most contractors won't pay the price & say, instead, it always crks,,, please pass the pepper :laughing:


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## concretemasonry (Oct 10, 2006)

iditit -

When you put a 20x24 slab 6" thick in the ground, there is a very good chance it will be used for other purposes. Only in the U.S. are people so stupid to build for today and forget about tomorrow.

ghidley -

Sell the scrap and do it right. It really won't make a big difference in the job. If I was doing it myself, I would also put poly under the slab, but that may not be necessary in San Diego, despite the low cost.

When you convert it to a shed/garage by enclosing it, and if the next owner's wife wants to put down a laminated or wood floor, you have a seeling point. You never know what will be a plus but you find out about the negatives if you don't do it right. The cost difference is not that much, especially if you are using your own labor.


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## yesitsconcrete (May 11, 2008)

6mil poly was the spec on mil jobs,,, lately we've seen 15mil come into the workplace,,, all i've seen it do is add cost, dick.

you make a great point that's often forgotten,,, if you don't have time to do it right the 1st time, where in hell're you EVER going to find the time to do it over,,, OR, as 1 of my inspectors said upon finding my guys'd ' forgotten ' to install backer rod on 1/2 mile of longitudinal jnt which was already sealed, ' how do you intend to remove the sealant, place the forgotten backer rod, & reinstall the sealant ? ',,, they never forgot after that


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