Asphalt pavement to concrete slab continuous joint detail

[MonsieurR]

Hello everyone,

I'm on a project where the interior pavements are 6 inch slabs with a 8 inch base layer, and the exterior pavement is 3 inch asphalt with an 8 base layer and no subbase. Subgrade is pretty good (CBR >20%). The project is private and the biggest load will be occasional service trucks. I'm only worried about the transition between this pavements, as in one place they must be aligned and I worry that if not properly compacted the asphalt will deform more than the concrete and the joint will not be very smooth. I used to have a drainage channel with a steel grate to sort of help yet it was removed. What is the joint details that has worked for you in similar situations? I have seen a lot of details on the streets with some problems.

Kind regards.

 

[oldestguy]

I'd at least have the same subgrade elevation for each and taper up that to the flexible pavement say in about 4 feet. If subjected to freezing, expect some difference in later years. Likely the flexible will drop some, probably due to the rigid being up more than when built. If possible compact the asphalt when still very hot and slightly higher.

 

[Ron]

Slope the vertical face of the concrete transition at about 20-30 degrees. This allows the asphalt interface to always be pushed against the concrete, thus more likely maintaining a closed joint between the two. It also provides additional support to the asphalt pavement at a high stress area.

 

[dik]

3" asphalt with 8" base might be a bit light for any service vehicles...

Dik

 

[MonsieurR]

Thanks for your suggestions!.

dik, the pavement has very low traffic, you think there might be rutting problems for high loads? Those thicknesses are common here. Base is chemically stabilized.

 

[dik]

thanks... Dik

 

[Ron]

MonsieurR....rutting is controlled by the deflection (i.e.,stiffness) of the subgrade. You do this by building the pavement from the bottom up as OG suggests. Stabilize the subgrade, provide a competent base, and provide adequate thickness of the asphalt to minimize asphalt cracking (stress level at the bottom of the asphalt layer controls asphalt fatigue cracking).

Here is a detail of the sloped concrete transition. This was done for a light traffic municipal street with no freeze/thaw issues....

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1524651335/tips/Asphalt_Concrete_Transition_lfatdl.pdf[/url]

 

[dik]

Ron: and the asphalt doesn't fail at the junction of the concrete and asphalt?

Dik

 

[cvg]

I am surprised you are not using the agency standard driveway, curb, gutter details for the transition between public and private roadway. If there is drainage across the road at that point, you will probably need a concrete gutter. A 1H:8V batter on the face of the concrete is sometimes used, however a vertical face is generally acceptable.

 

[Ron]

dik...no, but then our asphalt easily gets to 130-140 degrees in summer so it gets remolded against the concrete pretty easily. Have used this or similar detail for about 25 years.

 

[dik]

thanks... Dik

 

[MonsieurR]

Sorry, attached you will find a picture of the situation. Interior pavements of the building is 6 inch concrete and exterior is asphalt.

I finally ended up putting a small T steel shape in between. Its a detail I have seen (nor particularly elegant). Standard driveway curb is not very appropriate and client wants a "smooth joint".

thanks for all the comments.