# What might they do with pulverized concrete? **URL:** \ **Category:** Factual Questions\ **Created:** [October 30, 2013, 9:14pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686 "2013-10-30T21:14:29Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![EdwardLost](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@EdwardLost](https://boards.straightdope.com/u/EdwardLost)\ **Post date:** [October 30, 2013, 9:14pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/1 "2013-10-30T21:14:29Z")
There was an office complex demolished nearby. After they removed the building debris, they pulled up the concrete foundation and dumped the chunks into a crusher which deposited the bits into a huge mound. Now they’ve covered the mound with black sheeting. Why might they have done this? I assume the sheeting it to keep down the dust, but why leave this big mound of crushed concrete on site? Can it be re-used for the foundation of the new building(s), or is this just temporary storage? ---
**Author:** ![Civil\_Guy](https://avatars.discourse-cdn.com/v4/letter/c/d78d45/32.png) [@Civil\_Guy](https://boards.straightdope.com/u/Civil_Guy)\ **Post date:** [October 30, 2013, 10:00pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/2 "2013-10-30T22:00:42Z")
Probably useful as simple crushed rock, for use under foundations and roadways, and where a sort-of pipeway for underground drainage is needed. ---
**Author:** ![davida03801](https://avatars.discourse-cdn.com/v4/letter/d/b5e925/32.png) [@davida03801](https://boards.straightdope.com/u/davida03801)\ **Post date:** [October 30, 2013, 10:28pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/3 "2013-10-30T22:28:38Z")
Most likely to be used as non structural fill. Perhaps this varies with local codes and such but I am not sure that crushed concrete would be accepted as structural fill underneath a building. I know for some engineers that would not be accepted. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [October 30, 2013, 10:34pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/4 "2013-10-30T22:34:44Z")
It’s probably covered to keep down any friable material. Lime is not conducive to healthy lungs and I would suspect that it’s against local codes to leave it exposed to wind (and rain, for that matter, as you probably don’t want it leaching into the soil). From Wiki: > [@](#): > > Concrete recycling[edit] > > Main article: Concrete recycling > > Recycled crushed concrete being loaded into a semi-dump truck to be used as granular fill. > Concrete recycling is an increasingly common method of disposing of concrete structures. Concrete debris was once routinely shipped to landfills for disposal, but recycling is increasing due to improved environmental awareness, governmental laws and economic benefits. > Concrete, which must be free of trash, wood, paper and other such materials, is collected from demolition sites and put through a crushing machine, often along with asphalt, bricks and rocks. > Reinforced concrete contains rebar and other metallic reinforcements, which are removed with magnets and recycled elsewhere. The remaining aggregate chunks are sorted by size. Larger chunks may go through the crusher again. Smaller pieces of concrete are used as gravel for new construction projects. Aggregate base gravel is laid down as the lowest layer in a road, with fresh concrete or asphalt placed over it. Crushed recycled concrete can sometimes be used as the dry aggregate for brand new concrete if it is free of contaminants, though the use of recycled concrete limits strength and is not allowed in many jurisdictions. On 3 March 1983, a government funded research team (the VIRL research.codep) approximated that almost 17% of worldwide landfill was by-products of concrete based waste. Also: > [@](#): > > Dust from rubble or broken concrete upon demolition or crumbling may cause serious health concerns depending also on what had been incorporated in the concrete. ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [October 30, 2013, 11:24pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/5 "2013-10-30T23:24:22Z")
> [@davida03801](#): > > Most likely to be used as non structural fill. (To clarify): You can [use it as base material](http://www.wolfpaving.com/Portals/98698/images/porous%20pavement_cross%20section.png) under parking lots, unit pavers, sidewalks, etc. They use crushed limestone chips for that one way or the other so crushed concrete could probably work just as well. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [October 30, 2013, 11:32pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/6 "2013-10-30T23:32:17Z")
This dust issue explains why the mall that is being demolished here in Charlotte was being sprayed like a 3-alarm fire when I drove past it today. ---
**Author:** ![EdwardLost](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@EdwardLost](https://boards.straightdope.com/u/EdwardLost)\ **Post date:** [October 30, 2013, 11:33pm UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/7 "2013-10-30T23:33:00Z")
Thanks, all. I guess they could use it on-site. I’m curious to see what they do with it. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [October 31, 2013, 1:24am UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/8 "2013-10-31T01:24:28Z")
> [@KneadToKnow](#): > > This dust issue explains why the mall that is being demolished here in Charlotte was being sprayed like a 3-alarm fire when I drove past it today. It’s also to knock down things like asbestos and fiberglass particles. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [October 31, 2013, 1:56am UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/9 "2013-10-31T01:56:23Z")
I hear it is a good mulch for tender Kudzu shoots. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [October 31, 2013, 2:08am UTC](https://boards.straightdope.com/t/what-might-they-do-with-pulverized-concrete/672686/10 "2013-10-31T02:08:33Z")
A few years back they were redoing taxi ways at the airport in St. Louis. The demolished taxi ways were crushed and used as base for the new taxi ways.