local recycle plant is making 3/4" concrete aggregate and sifting it clean to produce a 3/4" clean RCA. what is everyone's opinions on using for concrete slab sub-base within footings for basements and garages? seems if it is sifted clean and even rain washed a little, should be as acceptable as virgin source gravel. Think?
I would think it would work Whats the building inspector think of it?
used it a few times and build inspectors never had any objections, but slab pours don't really require a inspection. footing inspection, then backfill inspection. The inpectors see the RCA within the footings already when thay come for backfill inspection. I even been using it for the footing drain gravel. Heard some old time contractors mention about 1. alkali in the crushed concrete being bad for exposure to metal. Guess sump pump?? 2. residue concrete dust on RCA washing off and clogging drains.
really??
Around here recycled concrete has been used in a lot of applications for quite some time now. Not sure on the house, most of that around here is either pea stone, or sand. As for roads and parking lots, its part of the MDOT spec book. In fact, a large percentage of new work is built on crushed concrete. I find its a good product. You get more sq footage covered per ton compared to virgin stone. I also think the portland cement that is still in the crushed concrete helps bind it together. Just make sure the source is clean. It used to be the rule of thumb that if you ordered crushed concrete, you got wood, carpet, and anything else that came off a demo site. Thats has been cracked down on big time, and most places wont even accept brick to crush into stone any more.
Is that due to possible contamination from lead paint on the brick?
or is that because of the contamination??
I believe it is a spec issue. The way I understand it, MDOT will not accept brick as stone, since it is made out of clay.
Brick is a "deleterious" material - doesn't meet the freeze thaw resistance requirements.
Thanks Raildude: We don't "freeze" down here but we cannot use crushed brick in some circumstances (as a building product) until it is, by definition, "fines". We just call the concrete and brick fines "cracker dust" and its used very successfully on clay sites for building pads. Crushed brick or concrete is often used for private roads, farm tracks etc in wet areas.
Recycle has it's place and it's not virgin. We always get a spec. and use the spec. it's cheeper in the long run. The only real place that I would not use it, is in a traffic area because it breaks down. In Ca. there is really no price difference between recycle & virgin material, there used to be a 1/2 cost difference. If it doesn't say call the engineer and get a letter of record that way you can't ever get into trouble. Off topic political reference removed