for those who work on concrete highways

Maybe since each slab is indepandent then the joint does not matter as much . Plus they will problably just caulk it .

When HWY 84 was being constructed, a section from about Stanfield and running on up Cabbage Hill, was poured into a slip form and rebar was placed continuously with no joints in the concrete. The was done in 72-73 as an experimental section. It worked well and until a few years ago, little cracking took place. Still there are there are not enough cracks to justify replacing the concrete. Because of tire wear the surface wore down so a X section showed low spots where the tires ran, grinding was done and asphalt put over the concrete. The asphalt was typical HWY quality and it is not standing up to the loads put on it, not cracking but the ruts are back in some areas. The reason this technique was not used after the test was because of cost is what I hear, but the money saved over the years on maintenance should have covered that many times over. When I was hauling concrete for I-90 from Lookout Pass down through St Regis, the concrete was deeply scored to make the joints, drove on a bunch of highways constructed that way and there seems to be a grade change at every joint where frost heave is common.
jud

I would think that an access road for a concrete fire truck would have to be pretty strong.

Seriously, we have done a few roads without joints. They were slipformed on top of a 4" asphalt "bond breaker". At any end that joins a bridge or railroad track they had an I beam with 6" of styrofoam expansion material. I think contraction joints were saw cut about 2" deep and filled with caulk after the concrete cured. I can't tell you much about the design of it though.

James

> MY QUESTION.. do they still use such joints for continuos roads, excluding junctions to other structures.

David, I don't know whether you'll be able to access the material at this link:

Concrete Pavement Joints

I'd say that the laws of physics haven't made contraction or expansion joints unnecessary in concrete pavements.

After the concrete cures for a day, the slab is saw-cut every 25'+/- to a depth of 1/3(depth) to aid in cracking at the cut from cure-shrinkage. The crack can be .25" in places. Rubberized asphalt is injected into the crack to keep water out. Concrete expands about the same rate as steel and this usually takes care of the expansion.