My friend is building some new concrete steps to his back porch. He has some old chevy blocks , brake drums and general automotive iron he wants to get rid of . If these items are clean of fluids is there any reason we couldnt use them as fill in the steps.
Jimmie
I would not use them because as they corrode they will at first get bigger (Think about the flakes that come off your drums & rotors). Then as they corrode further you could be left with a substantial void.
If you don't want to take the junk to the scrapyard yourself then call the junk guy. Look in either Craigslist or your local paper usually in the cars for sale section.
Cinder blocks are cheap and sometimes free, again try craigslist.
I don't think I would use what you have, someone would likely be happy to take them off your hands for the scrap value.
On the other hand, I can remember my father using some old bed springs to re-enforce the front porch of our home about 60 years ago. It looks like that slab is still there in one piece.
How are they going to get bigger while they're encased in concrete?
Big problem in Florida - lots of buildings with balconies have had to rework the concrete. Rebar rusted, expanded and cracked the concrete. Some problems with the issue in our condo, but nothing structural. Building down the street, about 12 storey, had a great deal of work done for the problem.
Who likes tension? I don't like tension! For gosh sakes shut up about the tension or I'll....
This is MM's sister. MM has been taken to the hospital and won't be available for posting until the court-ordered psychiatrist has examined him and filed his report.
Haven't they been using rebar for 50 or 100 years? Did something change so that it rusts now?
No, you've been sleeping or in a coma. It's always rusted.
RIf he wants to get rid of the metal, just put it out by the curb on a non-trash-pickup day and people driving by will pick it up as scrap metal to sell to a recycle yard.
It really surprises me that you have such problems understanding this. Your personal observation of those funky brown stains on concrete structures everywhere should indicate that something is rusting. If you can't see what's rusting, and are keen enough to realize that rust doesn't just magically appear on concrete, you'll probably latch on that the rust is coming from inside the concrete.
In a nutshell. Concrete is not waterproof. It wicks up moisture. The steel doesn't care that it is encased in concrete and will rust in the presence of the H2O. Concrete sucks in tension - something on the order of 1/10 its strength in compression. Constant tension on concrete leads to cracking. Cracking allows in more moisture, and the cycle continues until the structure falls apart.
Please, DAG. There's a hole in your education.
R
Tell him not to throw parts under the trailer to begin with. Scrap metal is worth at least a 12 pack, that should get him moving.
There are worth a lot more at the recycle center.
Perhaps the problem in Florida is with buildings not kept adequately painted, so there is more salt intrusion. Don't know the reasons.
I guess all those engineers who've been building things with steel-reinforced concrete for all these years must be completely ignorant, huh?
New Obama law, maybe. The Rusting of Rebar Act of 2009.
From the results, some of them obviously were.
Your stance is that you can throw steel into a concrete pour and it doesn't do anything because, hell, rebar is steel. That's like saying that you can pour gas anywhere into a car since a car runs on gas. You know, nonsense.
Like I said, if you want to learn, Google the subject. I'll give you a head start. This is from Wiki on reinforced concrete:
"Common failure modes of steel reinforced concrete Reinforced concrete can fail due to inadequate strength, leading to mechanical failure, or due to a reduction in its durability. Corrosion and freeze/thaw cycles may damage poorly designed or constructed reinforced concrete. When rebar corrodes, the oxidation products (rust) expand and tends to flake, cracking the concrete and unbonding the rebar from the concrete."
And this is from the Canadian Research Council:
"PREVENTING REBAR CORROSION IN CONCRETE STRUCTURES by Shiyuan Qian
This article reviews the issue of rebar corrosion, discusses some of the preventive technologies available, and presents information on recent studies conducted by NRC=92s Institute for Research in Construction.
The corrosion of reinforcing steel bars is one of the main causes of deterioration of reinforced concrete structures in North America. It has become a serious, widespread problem, with repair costs now in the billions of dollars annually. Whether the corroding rebars are seen exposed on delaminated bridge decks or piers, or observed in damaged parking garages, engineers and contractors are all too familiar with the problem, as are anxious property owners who call on them to provide solutions."
It's either odd that;
1). these guys are in collusion and making this stuff up or 2). you've never noticed it.My bet is on the second.
The main reason that the OP shouldn't throw the scrap iron in the steps is because it is wasting money. The second reason is that the random steel "reinforcing" will eventually cause problems.
I'm taking the liberty of cross posting this to some other groups with more knowledge on construction than this one. Let's see who weighs in and which way the verdict goes.
R
RicodJour,
You do realize you're wasting your time, don't you?
That's why I cross posted. I figured Doug might not appreciate the messenger. ;)
R
From what I've seen (& read) working in the civil structural field for since 1988, the major cause of reinforced concrete failure is inadequate coverage. Followed by poor quality concrete.
Depending on the "exposure" & environmental conditions, as little as
2" of coverage is spec'd, harsher conditons 3"+ or more.Epoxy coated rebar is a "new, hot" thing but I'm not convinced that it is "the" solution. Epoxy coating can get damaged during placement, leaving bare steel. :(
I'll put my money on extra cover and good concrete, designed for the local conditions.
Rebar that is fully encased in sound concrete with adequate coverage will last a LONG time.
Too little coverage or poor quality concrete will allow the rebar to begin to rust....the rusting rebar will "disassemble" the rest; quickly at first as it attacks the surface rebar but much more slowly as it progresses to the deeper rebar.
The Huntington Beach, Ca pier (the original one....ca1900) needed to be replaced due to impending structural failure. One of the engineers on the project (evaluation of the old pier) told me that IF the coverage had been adequate, the peir could have been repair and served another 50 years or more. But due to poor coverage the pier had to be demo'd and replaced.
cheers Bob
I think it is a matter of construction and maintenance, not engineering. On our condo, there have been several areas where rust caused bursting of the concrete. Perhaps rebar was too close to the surface, or cracks in stucco not patched and painted, allowing moisture and salt intrusion. Another place was a concrete sill by a patio slider. We also have iron railings on our balconies and atrium deck which are embedded in structural concrete. They are the same railings used inside condo units
- the anchor is embedded and then the railings bolt onto the achors. The exterior ones rusted badly years ago, to the extent that some rusted through and the attachment was no longer identifiable. Along the atrium deck (second story), several places where the anchors protrude busted out the concrete. After grinding out the rust and patching and painting, they hold for several years without further bursting of the concrete. Enough anchors intact that nothing is loose. Several years ago, it was a pretty big issue for condominium management companies - can probably google up more info if you are interested. Perhaps it isn't an issue at all if not near salt water.
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