Pavement debris as engineering fill

[Gimbli]

My doubt is simple. Can pavement debris be used as engineering fill even it classifies A-2-4? I mean, does this material develop the same stregth as an A-4 when compacted to more than 95% Modified Proctor?

 

[cvg]

how can you test broken concrete and asphalt using proctor? If it is pulverized to form aggregate, than it probably can be used.

 

[SlideRuleEra]

The volume of the area to be filled is a consideration. A few years ago we solved two problems:

1. What to do with several thousand cut-offs from 10" square concrete piling?

2. How to find additional suitable material to fill up an existing borrow pit so that an above-ground industrial ash disposal pond could be constructed on the site?

With our Geotech's blessing, we had the pile cutoffs (as-is) put in the borrow pit , more or less in layers, surrounded by suitable soil. This was in a seismic area, too.

http://www.SlideRuleEra.net

 

[civilperson]

Yes, totally suitable if placed in lifts and compacted to specifications. This is high quality fill compared to most borrows, only pit and quarry sources could be considered superior.

 

[EdGeotech]

We have used recycled pavement as structural fill successfully on a number of projects. However, environmental engineers on our projects are always hesitant to allow recycled AC under buildings. So, we try to use up as much of the recycled material as possible in pavement areas, etc.

 

[Ron]

Yes, pulverized pavement materials can be used as engineered fill. Keep gradation within ranges you'd use for other select fill materials. You should note that concrete pavement contains a lot of unhydrated cement that will react after compacted and create a material that can be difficult to excavate.

 

[geodan]

We have allowed crushed/pulverized pavement-concrete materials to be used in a variety of structural fills. Depending on the post-develpment use, we have specified different gradiations or a different maximum particle size.

In general, for light loads (shallow foundations and parking areas) we usually recommend the crushed/recycled concrete debris be crushed to attain a well-graded mix with maximum particle size no larger than 2 inches. When then placed in 8 to 12 inche lifts and compacted with a large vibratory roller, it generally has high density and strength values.

Testing the fill with a nuclear gauge is usually not accurate. We typically observe construction, note the amount of compaction effort and check to see how it holds up under fully loaded construction equipment.