Coeff. of static friction between concrete and asphalt

[jdonville]

Anyone have a reference for static friction coefficient for mass concrete on asphalt pavement?

I am trying to evaluate the effectiveness of using a standard traffic barrier section as a retaining structure for a modest (2-foot high) fill. The traffic barrier is normally cast-in-place on top of the intermediate asphalt course using a slipform.

Jeff

 

[civilperson]

Dowels drilled into the existing pavement is the detail that I am familiar with for Barrier cast on existing pavement.

 

[jdonville]

civilperson,

My situation involves bituminous pavements - no dowelling.

Jeff

 

[COEngineeer]

Do a test to figure it out. When I need the friction coef. I always use a low number so I design it more conservatively. But it looks like you want to see how effective it is so you probably need a good number. Put a concrete block with known surface area touching the pavement with known weight and pull it with spring scale. Just an idea. But since it is a cast in place situation this test is probably not valid. Maybe you need to cast in place the test also and figure out the weight after you pull it.

 

[jdonville]

Thanks for the responses.

I think I'll just specify some embedment into the bituminous pavement section and choose a conservative Kp, or recommend dowelling into a concrete pavement.

Jeff

 

[aeoliantexan]

Isn't bitumin thixotropic? Bitumen coatings are used on piles to reduce downdrag because they can resist the short-term loads of driving but slip under prolonged loads. A test would need to be long-term and under the highest expected temperature.

 

[civilperson]

Dowels are used with flexible pavements, usually # 4 rebar with 6" embedment driven in a 1/2" diameter hole on 4' centers.

 

[BigH]

Jeff - just saw something on NatGeo today about barrier testing. A NJ barrier withstood huge truck hitting it (not sure it if it was "tied in" or not) - compared to a new plastic modular unit that let a pick-up truck hit it and shove the whole string back - and then the pick-up truck jumped over the unit. Interesting few minutes of viewing.

 

[Panars]

Jeff-

I asked around and I have been shown some test data on portable concrete barrier on asphalt pavement. The results indicate a static friciton coefficient of about 0.55 to 0.6. I would use a value of about 0.5 to be a little conservative.

 

[chicopee]

JDONVILLE, we used full size and half size Jersey barriers on bridge jobs on I95 and we always had to anchor them to the aphalt pavement eventhought the barriers were pinned together and traffic ran parallel to the barriers. Are you not concerned about traffic collision?

 

[Panars]

He is using it as a low retaining wall. If there is a vehicle collision, the soil behind the barrier will provide additional resistance.

I was driving the Pennsylvania Turnpike this weekend, and it looks like they use barrier as a retaining wall along the western part south of Pittsburgh.

 

[PEinc]

"... use barrier as a retaining wall along the western part south of Pittsburgh."

The PA Turnpike is also doing the same in the Philadelphia area right now.