Crushed Concrete Density?

[hangontight]

Just wondering if anyone has a good average density for crushed concrete pavement. Our crusher makes it into 4-6" aggregate and I'm trying to convert cubic yards to tons. Also, I have the same question about Recycled Asphalt Pavement..anyone have a density for that? Thanks for any help.

 

[Ron]

Hangontight....With pieces that large, your density will not be high...likely on the order of 90 to 100 pcf for the crushed concrete.

If it were crushed in the manner of a graded aggregate base material, the density would be upwards of 120+ pcf.

RAP will be somewhere in the 90 to 95 pcf range, depending on gradation.

 

[Dozerman56]

It varies some depending on the density of you local aggregates used to make the concrete, and on your percentage of voids. For the product you're talking about here in my area I'd figure about 110-115#/cubic foot.

 

[msucog]

you talking about densified in place or loose in back of haul truck?

i've seen heavier RAP (i want to say it ran about 125-130 pcf compacted but i'd have to double check since it's from a soil cement job i did a few years back)

 

[Drumchaser]

Sorry not much help here:

I have not seen any recycled concrete base that large used for roadway base. Largest has been 0-10% retained on the 1-3/4".

Also have not seen any RAP used as a base material. Did use an Iron Ore / RAP blend on a project (mostly I.O.) and the Da was around 135 pcf.

 

[msucog]

i never used crushed concrete that big for pavements (other than stabilization of undercuts or a few feet below subgrade) but used rap in a soil cement design to cut the cement required versus using straight soil.

 

[caddyr2]

I was asked to figure the piled density of some crushed concrete for a job I am working on. I recieved a sample and it is very clean and is about 2" to 3" pieces. I notice alot of brick mixed in. Using a pot of known density and lightly dumping the sample in the pot I ended up with a density of 82 PCF. Seems terribly low but with the 20% +/- brick does this sound possible? It has to be since it was actually measured out and tared here in the lab. What do you guys think?

 

[concretemasonry]

caddyyr2 -

You discovered the high variability of the density of larger particles. The weight/density of 82 pcf could be accurate for that sample.

Large (4" -6") pieces of concrete are generally cubical and angular.

The in-place density depends on the size and shape of the individual particles. Large pieces with no fines will give you a very low density (pcf) unless you have the optimum amount of fines of the correct gradation. - A one cubic meter of large spheres has a give weight. You can add a large amount of "marbles" in between the "grapefruit" and increase the weight of the cubic meter of materials without any compaction.

Cubic materials can be difficult to compact the solids because of the shape and friction. Physical vibration(compaction) does little to increase the density of large particles, while moisture and vibration can get much higher densities approaching 145 pcf.

 

[Ron]

caddyr2....not out of range. The dry rodded unit weight of coarse concrete aggregate will be in that range and slightly higher for normal specific gravity aggregate.