[logfromblammo]

Damage to rigid pavements occurs more often in climate zones that experience multiple freeze-thaw cycles at the ground surface during a single winter. Many of the populated places in Canada freeze one or two times at the onset of winter, then stay frozen until the thaw, with maybe one more freeze after that.

Southeast Ontario, New York, Michigan, Pennsylvania, Ohio, etc. will re-freeze near the surface dozens of times every winter, and each time, more pavement damage is possible. Halite and other ice-melting chemicals can exacerbate the problem by making the ice in or under different parts of the pavement freeze at different temperatures.

You don't even need to do it properly the first time. You can seal pavements (and the underlying soil) against moisture infiltration at any time. Dropping a layer of asphalt on top is a common way to do this after the initial construction. Many places in the US simply do not bother, because that would cost a lot more up front, and then there would be fewer maintenance contracts to hand out. There's always the possibility that no one will ever complain, and the problem can be ignored forever--that's money that never needs to be budgeted.

If you build a proper foundation for a sidewalk, and then seal it against moisture, it will stay smooth and level for hundreds of freeze-thaw cycles, barring some natural disaster that would let the water underneath it. But if you're only mayor for two years, and the sidewalks last 30, nobody is going to come back to you 20 years after you leave office and pat you on the back for your wise sidewalk decisions. It is more likely that there will be some crisis right before the election and the money that could have solved it already went into great sidewalks. Or even worse, if you're a subdivision developer, you're out of there a year after the last lot gets sold, long before anyone notices how many corners you cut on the sidewalks.

All of this comes back to the prevailing attitudes in the US about who should be responsible for community infrastructure. We often expect private entities to build it, and public entities to maintain it. This screws up all the incentives. The reality is that subdivision developers probably should not exist. The municipality should be performing that function, instead of annexing every ad-hoc, ex-farmland housing development that springs up on the borders. That's how you get straight streets that connect at both ends, and good sidewalks that go everywhere that cars can. And then you can fire the zoning board, because when you build all the streets, you can control all the lot sizes and business parking requirements directly.

[oneplane]

Not sure why it all has to be paved, using tiles or bricks works fine here.

We do have some problems with ZOAB-based paved roads if the freeze/thaw cycles are too high, but any big problems are repaired in two or three days, and all roads are maintained and replaced relatively quickly anyway, so it's not a big deal.

It's strange to see the broken roads and patchwork in the US. Every time I visit I wonder why there is no majority that agrees on fixing it. Short term "it works now" is such a bad idea...

[logfromblammo]

That definitely would not work in Atlanta. They don't have the freeze-thaw problems there, but using tiles or bricks is a horrible idea, for two reasons: weeds and ants.

When weed seeds fall into a crack and germinate, the roots dig down into the sandy substrate looking for soil. If you prepare the foundation correctly, the weeds die before establishing a viable foothold. So then you have a choice. Pull the weed out, and the crack widens and a little bit more of the substrate is disturbed, or let it stay there and decay, leaving some nutrients. Either way, they next weed seed that lands there will have a much easier time of it. No matter what you do, decaying organic matter will eventually filter down under the sidewalk surface, and something will be able to grow in it. Temperate evergreen pines and magnolias drop leaves all the time--not just in autumn--so you would have to sweep them off daily.

Ants just love making huge excavations one grain of sand at a time. If you build a brick sidewalk, and do not continually spray it with ant-killing insecticides, you will eventually experience a big section of it collapsing into swarming ants, possibly without any obvious prior indications that ants were digging under the sidewalk.