Why do I see entire parking lots get a coat of sealant, but never really see streets or highways get a large coat of sealant?
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For example: [https://youtu.be/Lmd1r0P0GWE?t=192](https://youtu.be/Lmd1r0P0GWE?t=192)
In: 709
This looks like a fog seal. emulsified asphalt is being sprayed to seal off the cracks and keep water out of the cracks (also referred to as a crack seal for this very reason)
We do this on roadways, however due to the slickness and long term durability- an aggregate is also added. This is what we call a seal coat or chip seal. This is more of a maintenance operation. For new asphalt we place a tack coat instead of a fog seal to help it bind with the layer underneath
They do, it’s just a different sealant. For example, the Texas Department of Transportation has just under 298,500 lane miles (i.e. if a road is 2 center miles long and consists of 2 lanes, one in each direction, that is 4 lane miles) of roadway under it’s jurisdiction. TxDOT maintains a 7 year seal coat rotation meaning every 7 years a sealant is applied to all aggregate roadways (concrete paving will sometimes get a seal coat as well depending on it’s condition and whether or not the contractor was paying attention to what they were doing). The sealant isn’t a seal coat like referenced above though but a chip coat. It essentially consists of a based seal coat and then a rock coat on the sealant while it is still wet. This provides traction and allows water to run along the rock layer instead of on top of the roadway.
Most of this work is done in summer and depending on the condition of the road, minor resurfacing may also be performed at this time as well. There’s more that goes into it but that’s the basics of summer road work in Texas…
Source: Former TxDOT inspector
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Actually, they do – it’s called Chip-Seal, it starts with a spray of very sticky sealer, then they add a fine gravel, then after some time, they add another spray of sealer. Typically done on secondary roads.
[https://youtu.be/n7iW_Rpk2Go?t=118](https://youtu.be/n7iW_Rpk2Go?t=24)
They do! It’s usually called a micro lift, seal coat or something similar. They put rock on it that’s like Kittie litter that provides grit. They typically do this on lower speed local roads to keep everything together for a few more years. On larger roads they’d either reconstruct or mill the surface and overlay it.
We do periodically seal coat long stretches of highway in Idaho every summer. It adheres a small layer of rock chips to the roadway to increase traction during the winter and reduce oxidation of the roadway, extending the lifespan of the asphalt.
Municipalities with smaller budgets do give some of their older asphalt road a slurry seal to make them last longer. The tar is for larger cracks. Anyway to keep the water from getting into or under the road surface in the winter months saves money in the long run.
Well, they do. There’s a fog seal which is something you see on a parking lot. Various intermediate lifts up until you get a top lift, about 1″ of asphalt on top of an existing road.
Depends where you live. In California I’ve seen cities put stuff down to extend the life of asphalt
Also parking lots are usually private property and street are municipal property
Government waste.
It’s cheaper up front and easier to give contracts to a construction company to do a shit job every 2 or 3 years than it is to pay more up front to a company to resurface a road the right way 1 time.
When you’re on annual budgets in a municipal government they’re going to choose the option that’s cheaper short term than it is to do the more expensive thing that lasts longer because they have budgets to work within. But they also have to justify their budget every year, which is the incentive to spend to that budget. And that is how the cycle of government spending —> tax increase—> more spending begins.
if you know you need to resurface a road every 2 years you can build that into your budget. If you don’t know when you’ll need to resurface the road because you had it done right and expensively, it’s harder to predict when it’ll need to be done again. Could be 5 years or 10 years or more. But that means there would be uncertainty in the governments budget and the idea of shrinking the budget and lowering taxes is unpalatable for a government.
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