Concrete Drag Strip

[VFF]

Hi everyone,

I am currently designing the replacement for the first 500 feet of a dragstrip with concrete, to tie in with the rest of the existing asphalt track. I want to keep the joints down to a minimum, or eliminate them, and I was contemplating using continuous reinforced concrete pavement. The width of each lane is about 30 feet. Because of the speeds involved, I also need to have a super flat slab.

So...is the use of a truss vibrating screed followed by ride on mechanical trowels, with a continuous pour for each lane, the best way to achieve the required flatness, or are there better ways?

For the steel design, I don't want to put longitudinal joints down the centreline of the track, so has anyone had any luck with a 30 foot wide continuous slab with reasonable steel for crack control? Typically, a CRCP would have heavy longitudinal steel, with fairly light transverse steel. However, I may need lots of steel in both directions! I am looking at using a lean mix concrete sub-base.

I can't prestress transversely as there are existing concrete barriers prohibiting this. I am reluctant to prestress longitudinally because I am concerned that with this length there will either need to be several joints, or in time there may be a large gap at the asphalt interface. What would be a ballpark typical length for economic prestressed slabs on grade?

Thanks in advance. I love this site!

 

[GeoPaveTraffic]

I hope you get a lot of comments on your most unusal project. I will offer a few.

First, have you contacted ACPA? They have local reps over the US, I'm assuming that the project is in the US otherwise... They may have some ideas for you. I doubt that you can create a slab 60 feet wide by 500 feet long with no joints and not cracks. Just don't think it can be done.

Buy if you really want/need to do it, I would eliminate the lean concrete base and go with crushed rock instead. Load bearing capacity is not the critical issue and the cracking pattern of the lean concrete will try to reflect through the surface concrete. Put in the crushed rock and drainage. Second, if you need a really smooth surface, I would plan on diamond grinding following placement of the concrete. Do that and the concrete finishers can just worry with the concrete and not the flatness. If it just needs to be smooth, then a truss screed or preferably a roller screed followed by a 10 foot pavers straight edge should be fine. I would not use power trowels.

You are always going to have a bump and maintainence problem at the junction of the concrete and asphalt, no way around it.

Good luck.

 

[cvg]

look at typical design parameters for runway paving. These carry incredible loads, cannot tolerate cracks (because sucking a chunk of concrete into a jet engine is very expensive...) and are designed for very high speeds. Joints are used, and don't seem to be a problem for the jets.

 

[ACtrafficengr]

The main difference I can think of between runways and dragstrips are jet engines don't apply much torque to the surface. On the other hand, the loads due to the brakes of a landing cargo plane may be similar, although of opposite sign.

"...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

 

[cvg]

assuming a large jet which may weigh upwards of 600,000 pounds fully loaded when landing at speeds close to 120 mph (perhaps faster) and then coming to a full stop (momentum is 72,000,000 lb/fps), I would guess that the force on the pavement is well in excess of that applied by a 2,000 pound car, even given the fact that the car accelerates much faster than the plan decelerates. Granted, the engines are reversed to help stop the plane, but the wheels also provide much of the stopping force.