Reinforced pavement

[jorje]

Hello everybody,

I am designing a road connection to a storage area. We have a strong turning to left. Because in this corner the big Truck will make BIG frictions i am planning to reinforced the asphalt pavement. Does anybody use something like that before? Please, let we discuss here.

Thank you.

Jorje

 

[Maury]

The same affect happens at intersections, where trucks brake to a stop. I expect that braking is harder on the pavement than a turning movement, but I don't have calculations to prove that. You say you are going to reinforce the asphalt pavement. How do you intend to do that?

 

[ACtrafficengr]

NHTSA requires large trucks to be able to stop from 62 mph in 335 feet, or an average acceleration of -24 ft/s (-.74 g). I've heard trucks will start to tip at 0.3 to 0.5 g, so yes, braking puts more stress on pavement than turning.

Jorge, I suggest careful construction and proper tack coats between lifts to ensure your asphalt lifts adhere to each other, and perhaps a Superpave or Stone Matrix Asphalt to handle the loads. Hopefully a pavement maven will wander by and give more helpful advice than this traffic geek can supply. I've heard Superpave is tricky if you haven't worked with it before.

I did once see a wire mesh product that could be embedded in asphalt. The pavement Ph.D. I asked was doubtful.

As an aside, truck braking performance is an engineering problem, not a physics problem:

a = F/m = fN/m = fgm/m = fg

If you could get big enough brakes to dissipate the kinetic energy and tires sticky enough to avoid skidding, a fully loaded truck could stop like a Porsche. Of course, this assumes the driver could keep it from jack-knifing and rubber side down!



"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[jorje]

First of all I would like to thank you all who gave me an answer to my question.

And on the question - for me more important are the forces during the turning of the truck.Why - because the truck will drive with speed 5-10 km/h which is nothing. But during the turning very big frictions are possible to be seen. Also my idea is to reinforced only the corner. The rest pavement will be normal an asphalt with construction for heavy traffic.

I also remember, that I saw before that they using for reinforcement Geotextile. I am searching know the catalog to see the name of the product.

So, let we thing about this case, please/

Thank you.

Jorje

 

[ACtrafficengr]

Most asphalt reinforcement I've seen is used to prevent cracks from propagating up through fresh asphalt overlayed over old pavement. You want to prevent 'shoving' and 'tearing' due to lateral loads.

Hmmm. Large trucks, moving at walking speed - is this a mine road or something similar?

Have you considered using cement concrete for the intersection and its approaches?

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[GabionGuy]

I would suggest looking into a material called Road Mesh. It is woven wire mesh reinforcement specifically designed for asphalt pavement reinforcement. It is a 3 dimensional reinforcement (approx. 5mm thick), unlike geosynthetic reinforcements.

 

[jorje]

GabionGuy - thank you for the idea. I already check this Road Mesh. It is a good material and if nothing else, most probably I will use it. I am waiting now for some more technical specification from their local representative.

ACTrafficengr - thank you for proposal. I will compare two methods and I will decide. And as I said this is local connection from the main street to some storages. That is why the speed will be very small.

Thanks to everybody,
Jorje

 

[BigH]

I might also suggest that you use CTAB (cement treated aggregate base) for the base course in this area. It should give you better performance in that your base course will not be subjected to the centrfugal "forces" - only your asphalt. If you are so worried about it - why not use a plain unreinforced concrete pavement?

 

[jorje]

Hello again,

So after final discussion with the client we made decision to use Concrete pavement instead of Asphalt. Is it possible for someone to show me some details for connection between concrete slabs with anchors? Also because we will use load of the truck 40-45 tones what will be the properly thickness of the construction? My thinking is for 40 cm Crash stones on very good compacted surface and after that 20 cm concrete with double mesh reinforcement (up and down).

Thank you in advance.

Jorje