Comment by prepend | Hacker News Reader

Comment by prepend | Hacker News Reader

It looks like a 60 lb bag is only $26 [0] and really seems to not require mixing, just tamp down and roll over. At that price, I think I’ll be a pothole vigilante.

It’s also surprising to me as I assumed that it was expensive to repair potholes and require special equipment and machines. This makes me think that any unpatched potholes are just a logistic issue since the cost is all labor and coordination.

Maybe this is finally a good case for blockchain as citizens could donate to an address and once the amount got high enough, some company would fix, make a claim, get verified, and get paid without needing someone to handle money.

But this gets us closer to distributed dystopia where towns are no longer competent to do basic stuff like send out a 3 person union crew for $300 to fix a pothole ($75/hour x 3 people x 1 hour + $26 + vehicle amortization). This also assumes dispatching for a single pothole. It seems like it only takes a few minutes so for a typical town (mine is 30 square miles) a crew could fix 2-4 potholes an hour or 16-32/day.

So 3x8x75 + 26x32 = 2632 before vehicle costs. Add in $100 for work truck amortization and maintenance and for $3k all the potholes get fixed.

[0] https://www.amazon.com/SAKRETE-Patch-Permanent-Pothole-Repai...

Cold mix, also known as “blacktop repair”, will repair potholes. I’ve worked with it before, I recall the packaging claims it will last 5-10 years. This is slightly misleading: if you cut the pothole edges square, make sure the base of the hole stays dry, tamp it well, don’t turn a car wheel on it or brake on it for two weeks, and it’s a driveway that gets maybe half a dozen uses a day, it will last 5-10 years.

From the pictures in the article, it looks like these vigilantes were not cutting the potholes. For keeping it dry you’re at the mercy of the weather. Tamping, let’s generously assume they used a pole tamper, which still does a mediocre job compared to actual machinery. These are public roads where you can’t control who uses them and how, so people will be braking and turning on the repair within a few hours. And again, public roads, these will see hundreds or thousands of uses daily. Given all these conditions, I’ll make an educated guess that the repair will last maybe two months, certainly less than a year. There’s a road near my workplace that two large businesses share, it’s at the bottom of two hills so it gets a lot of water running through, it’s an exit off a ~50mph road so it sees both heavy turning and heavy braking, and it supports approximately 1500 trips per day. Potholes there got really bad, repairs were made with cold mix because the local council was lazy and wanted to shut up complaints. They cut the holes and tamped with a tamping machine (looks like a beefy lawnmower, sounds like a dying motorbike). The repairs lasted less than two weeks.

(Eventually the council relented and did a hot mix repair - essentially cut out and dig up a dozen yard long section of the road and re-lay hot asphalt, as if building a new road - the road was closed for a few days, but that repair is going on a year now and is in better condition than the surrounding road. This repair required a back hoe, an asphalt truck [basically a concrete mixer truck with heating], and a steamroller.)

Why is a square the optimal shape? Is it because of the ease of cutting?

They are referring to a cylindrical hole or any non-tapered hole (i.e. "square" in the sense that the walls are perpendicular to the bottom).

I've also heard that a "keyed" hole works well- a hole that flares outward toward the bottom traps the solid chunk of asphalt inside.

I believe keying is now generally discouraged since it necessarily involves weakening “good road” around the pothole by undercutting it and replacing it with cold mix, which is fundamentally weaker stuff.

A neighbour filled a pothole outside my house with cold mix. With fairly low traffic, it lasted about 4 days before it was completely torn up, showering several parked cars (including my own) with sharp, sticky gravel

He either didn’t tamp it all, or tamped it very poorly.

I should note that I’m not against pothole vigilantism in general - in the same way that you can hire a pressure washing company or a lawn care company to bring some specialized tools and trained operators out to your property to do a really good job that consumer grade tools and a competent handyman simply could not achieve, my experiences with potholes have made me want a similar pothole repair service. A good road saw, premium-grade government-approved blacktop repair mix, a dedicated tamping machine, the proper training to install pothole repairs, and maybe even road plates to give the mix time those crucial first few days to set and bond? That’s achievable for a few thousand dollars of equipment and two guys in a work ute, I know because I’ve called asphalt repairs for the private roads in our business, and that’s what turned up, and they did a great job. Being able to call out a vigilante service like that for public roads would be a blessing and could definitely be run at cost on cash-in-hand donations from neighbors.

Didn't tamp it at all. Laid it on a wet road in the middle winter on an exceptionally cold and wet week.

> It’s also surprising to me as I assumed that it was expensive to repair potholes and require special equipment and machines. This makes me think that any unpatched potholes are just a logistic issue since the cost is all labor and coordination.

Cold patch is a temporary fix—it doesn't bond to the surrounding asphalt of the pothole. I don't know much about Portland's climate, and maybe cold patch will work well there long-term, but in areas with harsh winters, any cold patch in potholes will get ripped right out by vehicle tires since the cold will make it more brittle.

Permanent repairs usually do require machinery, as far as I understand.

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