Something I noticed

[wolverine]

The other day I was driving down a stretch of I-75 Just north of the Zilwaukee Bridge in Saginaw, MI. I couldn't believe how smooth the concrete surface of the freeway was. It was like driving on a brand new layer of asphault, but this was different. The concrete surface of the freeway was actually very old. It was that dark brownish beige color concrete turns after a few decades. The surface also had a mess of patchwork over various years of repairs. Now, the car I was driving doesn't have very good suspension. So bumbs are VERY noticeable. So why was the ride completely smooth?

Heading back at night, I noticed that my headlights were reflecting brightly off the surface. I was completely confused as to why it was so smooth. The surface looked incredibly abused from the Michigan winters, yet there was this weird reflective coating.

I asked some people at work who traveled that stretch more frequently than I did. I found out that a breakthrough technique was used back in the late 90's to repair the surface. Apparently, some sort of machinery moves over the surface and grinds down the top layer. An onboard computer keeps the grinding mechanism level so it isn't just dragging from section to section, but keeping the joints flush to each other on the surface. After that is done, the surface is sealed with something that knowbody seemed to know about. I guess it is some sort of protective chemcial for the concrete. I take it that this substance was reflecting my headlights. So this made me think:

Why not do this on all freeways across the state. I can't even remember the last time that portion of I-75 saw any repairs. Apparently this technique not only fixes the bumbs in the road, but prevents any further weathering from the surface. And in the event that it does fall into bad condition, the same technique can be used again to restore the concrete to a suitable condition. So if we used this technique, could an original concrete surface survive half a century or more without being replaced? If so, why the heck doesn't Michigan just stop wasting it's money on asphault (which only lasts 5 years in my area) and start pouring concrete?

If anyone has any information on technique described above, let me know. I'm curious.

[Allan]

Interesting. I'd like to know more too.

I totally agree about the asphalt. That's a lot of wasted money over the years, given its short lifespan. I have noticed that down here in Detroit they tend to use concrete more often for roads, most likely because it will last a lot longer, despite the inital expense.

[wolverine]

I totally agree on that point Allan, but what makes it most interesting, is that this new resurfacing method could help prevent major repairs to the surface in the future. Instead of giving a concrete surface a life span of say 30 years, we can give it a lifespan of 60 to 70 years instead.