I'm looking to have an asphalt driveway installed and the contractor wants to use crushed concrete as underlay. The area has a high water table and I'm concerned about the concrete breakdown. I have no experience with driveways but know enough to be dangerous I guess. Looks like about 7-8" of stone and about 2 1/2" asphalt proposed. Can anyone suggest what the proper underlay should be? Don't want to do this again in 5 years. Thanks
Crushed concrete can make a great road base. As long as your sub grade is hard and dry enough to properly compact the crushed concrete, you shouldn't have a problem. With the high water table, you may want to look into putting a geotextile(filter fabric) under the crushed concrete. You could also ask the contractor about using a 3/4"-1 1/2" quarry blend. It's more expensive but it's a natural product that will last forever. I think the concrete will be just fine for your application. Remember that proper compaction is the key. Hope this helped. Jim.
I wouldn't use the crushed concrete. If its exposed to high water, crushed concrete tends to break down rapidly in moist conditions,, like the previous post,,, natural rock last's forever. just my 2 cents.
Thanks for the replies. You guys absolutely helped.
I am a concrete recycler in NC. the crushed concrete will work great with the high water it will soak up more water than rock. some of the crushed cement will rehydrate and set back up and it will become harder than the natural stone. just make sure to let it cure 2-3 dry days before laying asphalt. most of the time when we put the concrete down in a washed out area of natural stone we will come back after a couple of rains the recycled concrete will still be fine the water will run across it and then washout the surrounding stone.
Just a side note here,,,, they are starting to frown on crushed concrete being used around our lakes,,, a yellow stream of yuk flows out of the concrete right into the lakes.
I pushed thousands of tons of recycled (old pavement) concrete into undercuts on an I-80 renovation. Sometimes four to five feet deep. State of Illinois inspectors watching all the while doing it. I
This from the guy who sells natural aggregates. Starting to see Mi frown upon using crushed concrete rip rap for drainage ways. They say it affects the ph, what do they think limestone does?
Lol... I can get the concrete for free to crush and sell, but I have to buy the natural agg. by the acre. I don't need the EPA coming after me for anything. They frowned when we used to use motor oil for dust control.