I was told once it’s because cities project the job to take say 5 weeks, so they rip it up the first week, leave it for 3 weeks, then repave the last week. And they do this so everyone gets a paycheck for the full 5 weeks. Surely there has to be a different reason?
In: Other
Where I live, a local high way was ripped and paved the same day. They had a caravan of equipment 3 or 400 yards long. The leading machines ripped the old asphalt, the next cleaned it up, then the pavers laid the new asphalt followed by the rollers. They did one lane at a time. They finished several miles in a single day.
Sometimes there is time needed from ripping it up to paving it to inspect the underlying material for competency.
For asphalt, that may mean the owner and designer needs to decide on the cost benefit analysis to remove more asphalt be putting a layer back on top and doing a more fully rehabilitation a subsequent year vs doing it now.
Sometimes it isn’t a surprise and part of the plan, this has been true for projects I’ve been nowhere it was asphalt paved over a concrete base. They needed a speciality contractor come and do a “falling weight test” across any cracks in the concrete to determine if there was sufficient aggregate interlocking to transfer load, or if some steel cross sticking would be needed, or if the whole section of concrete needed to be replaced.
ELI5: sometimes when you unwrap a present you need to decide if you want the gift or not
When they tear the road up go look for the diamond cutting tips they use. Occasionally you’ll find a few.
This is not always the case, but sometimes there are reasons to batch certain types of work. Say, for example, you’re a construction company who has to replace 5 streets. So first you do all the ripping up, then you do all the repaving. That means in between ripping up and repaving the first street, you first rip up 4 more streets in other locations.
I don’t work in construction so I don’t really know the logistics of this, but this is basically what they did when installing roundabouts in our city. Everyone was annoyed at the empty hole in the middle of their intersection, including at least one person who mindlessly drove into one.
It seems like there should be some kind of financial incentive associated with reducing the total impact to drivers, and maybe sometimes there are, but I think at least sometimes the construction companies are prioritizing the completion time of the total project over the completion time of each individual segment.
I read something the other day. I can’t remember the specifics. Substrate can only compact a certain amount of time in certain increments. I’m not sure if that’s the reason for letting it sit. It is one reason for the time it takes from start to finish.
Not to say it’s a perfect process, but in the example you gave I can shed some insight as to how it works for the company I work for.
We have hundreds of dump trucks, pavers, skid steers, asphalt plants, gravel pits, etc. but we contract out for things like our street sweeping, and asphalt milling. Why? That’s above my pay grade, but I’m sure there is a good reason.
When we start a road, we don’t leave it ripped up for weeks on end, but when the mill is there they run as hard and fast as they can as they get paid by my company per ton of asphalt that gets milled up. They will work 14-16 hour days, and can often work faster than the asphalt can get brought in. Sometimes a “mill and fill” is done where the paving crews are working 500-1000 feet behind the mills, but those tie up a vast number of trucks and make it very difficult for any other projects in the area to be completed.
If we have 15-20 trucks to put on a job it makes much more sense for those trucks to haul millings the first few days of the project, then haul fresh asphalt the next few days while the milling crew moves to another job, possibly working for a different contractor.
Our problem down here is they will rip up a street and take 3 months topit in new pipelines, then only partially pave just so it is no longer dirt. Then a year later they get it all repaved properly.
In New Orleans, sometimes it’s because we were given federal funding to make infrastructure improvements, but it had to be used within a certain timeframe. Our terrible mayor didn’t use it up until the time frame was almost over so in order to still get the money, they started a million road improvement projects around town and dug stuff up to get in under the deadline. And now some of this projects will sit torn up and partially completed for years lol
Sometime they rip up the road and then it takes a time to work on the lines, hydrovac, maybe replace some or repair some while the road is ripped up, then a few weeks to rip up and pour the concrete for the sidewalks, which my not been noticed if you are just driving down the road but it is slowly being completed. Then another day or more to sweep the now dirty road before new asphalt can be laid down. Then depending on the length of the stretch a several days to pave, and they may do one lane at a time so the asphalt has time to set a bit before it’s driven on. An inspector might come from the municipality which could be delayed. Suddenly several weeks went by, but it’s been being worked on the entire time. It’s just unnoticed by the general public.
Like many things construction related it’s all about coordination, or lack there of.
The people and equipment that rip up the road is not the same people/equipment that pave it. The efficient way of doing things is to schedule team A while team B finished up the prior job. Then team A moves on to the next job while team B moves into this job.
That way you never have a situation where team B is waiting on team A to finish.
The problem comes in when there’s a delay in either team. If there’s a team A delay, then team B will be ready before A is finished and that’s a problem. So normally they build in some buffer time into the schedule, a few days perhaps.
But then what happens is a delay on team B’s part. Then that buffer of a few days turns into a lot more days. Team A sticks to the original schedule but team B is now behind by 6 days. Then there’s another delay and next thing you know it’s weeks that B is behind by. Now rather than a tight package of team A finishing then team B moving in, now you have this huge gap.
What happens in some cities is that team A is really good at keeping a schedule but team B is not. might be problems with team B, might be crap equipment, might be weather related problems, might be a lot of reasons. But if team A sticks to the schedule but team B is constantly being delayed then the gap just keeps getting bigger and bigger and bigger 🙁
Latest Answers