Rigid pavement (parking area) design for tracked vehicles . 5

[SAJoseph]

Appreciate some references on pavement design for tracked vehicles (specifically military use).
- How do you design for abrasion? Use of polypropylene fibres or steel fibres?? Any surface coatings???
- Mix design: Min 40 Mpa, water/cement ratio, aggregate sizes and type??
- What to look out for in regard to placement and finishing.

Cant seem to find any military standards on this.

Thanks

 

[oldestguy]

Nothing in the publications from US Corps of Engineers?

 

[Ron]

I did a pavement design for a large Caterpillar dealer about 40 years ago. It lasted over 25 years until they demolished the entire facility to build a new Lowe's.

For abrasion resistance I would be careful with the concrete mix design...keep the w/c low and require good placement techniques. Use the largest coarse aggregate you can justify to keep shrinkage down. If you want to add fiber, use steel fibers. Poly fibers are worthless for abrasion.

I would also "armor" the joints. I used 4x4x3/8" angle on every joint. Make sure the joint opening is kept small so you don't get tracks caught in the joint.

 

[r13]

Concrete with 28 days compressive strength of 40 Mpa (≈ 6000 psi) is quite common in use. I'll say the w/c ration must be kept low to achieve the relatively high strength in aim, and minimize shrinkage. You might need to add additive to maintain workability during concrete pour. In addition to concrete mix and placing, duration and method of curing are quite important too. ACI has publication for concrete mix design. It covers most, if not all, of things you need to know to produce a concrete of quality.

Ron is correct, armor the expansion joint. I think you shall minimize/eliminate the construction/cold joint through construction planning and management. I think AASHTO shall have excellent guidance on joints design, also surface roughness and methods of finishing.

 

[epoxybot]

High abrasion resistance can be accomplished by incorporating a concrete topping. Trap Rock toppings are a common choice for abrasion resistance. High Abrasion and Impact resistance is usually dealt with via a metallic topping, such as Master Builders Anvil-Top 300. Anvil-Top is frequently used in Waste Transfer Stations, where front-end loaders frequently slam their buckets down & scrape/drive rubbish to the debris pit. Both Master Builders and Euclid have versions of these materials. There are a number of suppliers (Laticrete) & contractors that specialize in trap rock toppings.

 

[SAJoseph]

Thank you Ron, retired13 and epoxybot.
Ron - How would you "armor" the joints with the 4x4x3/8" angle?? is it an angle plate along the full length of the joint?? A sketch would be nice
Much appreciate all you nice folks.
Stephen

 

[dhengr]

SAJoseph & Ron:
In highly trafficked and regular turning areas, don’t the often embed steel plates or rails in the conc. slab? They are, or quickly become, the wearing surface or riding surface for the tracks or grousers on the tracks.

 

[Ron]

@SAJ and dhengr....that's correct. In areas of identifiable turning abrasion, rails are sometimes embedded in the concrete to help resist abrasion. The rails are typically small gauge train rails or bulb tees.

I will try to post a sketch of an armored joint sometime today.

 

[Ron]

Here's a rough sketch....

 

[SAJoseph]

Thanks heaps Ron!