demo'd struct, how to get concrete of...

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Author Message Bruce Konschuh Senior Member Username: brucek Post Number: 18 Registered: 08-2014 Posted on Wednesday, February 01, 2017 - 03:21 pm:    After a portion of a building has been demo'd, we have a request to describe the removal of concrete from rebar. I have asked 2 struct engineers, and they have no idea. Have you ever seen this done? or how is it done? ken hercenberg Senior Member Username: khercenberg Post Number: 1051 Registered: 12-2006 Posted on Wednesday, February 01, 2017 - 03:23 pm:    Is this to patch the existing or to recycle the rebar? Bruce Konschuh Senior Member Username: brucek Post Number: 19 Registered: 08-2014 Posted on Wednesday, February 01, 2017 - 04:13 pm:    recycle the rebar Jerome J. Lazar, RA, CCS, CSI, NCARB Senior Member Username: lazarcitec Post Number: 1734 Registered: 05-2003 Posted on Wednesday, February 01, 2017 - 04:22 pm:    as I read these posts, I am visualizing an old cartoon "guy walks into a bar"...doesn't it take more energy to remove the concrete from the rebar than you get back for recycling the rebar? Ahh, got to love Energy Conservation...but back to the question at hand, you take a chisel and a hammer and the rest is easy, pound, pound, pound. Jerome J. Lazar, RA, CCS, CSI, NCARB Senior Member Username: lazarcitec Post Number: 1735 Registered: 05-2003 Posted on Wednesday, February 01, 2017 - 04:28 pm:    We need Ralph to answer this question, I wonder if he's looking down from above and laughing? I asked my demolition expert, he just laughed at me. And said, are you kidding me? Guest (Unregistered Guest) Unregistered guest Posted on Wednesday, February 01, 2017 - 04:42 pm:    Pulverize/crush the concrete containing the rebar into little pieces. Use a big magnet to collect the steel. There are some videos of the process on youtube if you google "crush concrete with rebar." Although, this is means and methods. Not sure why you'd need to get involved with it. ken hercenberg Senior Member Username: khercenberg Post Number: 1052 Registered: 12-2006 Posted on Wednesday, February 01, 2017 - 05:32 pm:    Jerry, precisely why I asked. Not sure if the trade-off is worth it but not for me to say. Dewayne Dean Senior Member Username: ddean Post Number: 117 Registered: 02-2016 Posted on Thursday, February 02, 2017 - 09:21 am:    I would let the rebar recycler worry about it. It is not an easily done unless you have big rollers and crushers. J. Peter Jordan Senior Member Username: jpjordan Post Number: 934 Registered: 05-2004 Posted on Thursday, February 02, 2017 - 10:58 am:    I am with Dwayne here. We have a very good demolition company in Houston who has been around a very long time. Like they use to say about the meat packers, this firm recycles everything but the squeal. In this area, the crushed concrete is use for driveways out in the country. These guys can easily extract the steel for recycling and still wind up with a load of crushed concrete to sell. J. Peter Jordan, FCSI, AIA, CCS, LEED AP, SCIP ken hercenberg Senior Member Username: khercenberg Post Number: 1053 Registered: 12-2006 Posted on Thursday, February 02, 2017 - 11:06 am:    Gonna have to see about setting up a field trip for our local CSI chapters to see how it's done! James Sandoz, AIA, CSI, CCS, CCCA Senior Member Username: jsandoz Post Number: 206 Registered: 06-2005 Posted on Thursday, February 02, 2017 - 02:21 pm:    Fellow Houstonian, J. Peter, is correct. This demo company's operation is little short of amazing. Their facility is just south of the medical center and east of NRG Stadium where the super bowl game will be played this Sunday. In it is a 'mountain' of concrete chunks waiting to be crushed into smaller pieces. You can see the rebar is still with the concrete at this point. The pile is as tall as a six-story building. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 809 Registered: 10-2007 Posted on Saturday, February 04, 2017 - 04:24 am:    Who is asking the question? You have better things to worry about. I assume this is an issue because the owner needs a recycling credit. In which case all you need to say is that the rebar shall be recycled. The rest is contractors means and methods. If no recycling credit is needed you do not need to say anything other that the contractor is responsible for removing construction waste and disposing of it. I would not be surprised if the rebar was recycled in any case. J. Peter Jordan Senior Member Username: jpjordan Post Number: 935 Registered: 05-2004 Posted on Monday, February 06, 2017 - 01:35 pm:    Depending on the scope of the demolition, I would be very surprised if the rebar is not recycled. In most metropolitan areas, there are companies that will take steel "junk" and give you something for it. The demolition subcontractor could make an extra bit of profit from this or adjust his bid down so he gets the job. Steel is one of the most recycled materials on the planet. I don't want to tell the Contractor that he has to do it, but he is burying money in the ground if he doesn't. J. Peter Jordan, FCSI, AIA, CCS, LEED AP, SCIP John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1700 Registered: 03-2002 Posted on Tuesday, February 07, 2017 - 02:34 pm:    I've seen pincer-type jaws mounted on large hydraulic machinery. (Picture a 3 foot long wire cutter.) In a separate operation from breaking up the building, these jaws crush the concrete and it falls away from the rebar. The concrete chunks (not very uniform in size) and the rebar are separated and hauled away separately.