Road Construction

[mass88]

How are areas like Denver and Salt Lake City able to construct highways with concrete, but the Boston area is not?

What is the most durable material to use for road construction?

 

[Charlie_mta]

I remember back in the 1950s, the head of Mass DPW at the time, William F. Callahan, ruled out concrete pavement because of the bumpy ride that eventually develops from settlement of the slabs. So, apparently that has stuck as the policy through all these decades.

 

[JeffDowntown]

I remember back in the 1950s, the head of Mass DPW at the time, William F. Callahan, ruled out concrete pavement because of the bumpy ride that eventually develops from settlement of the slabs. So, apparently that has stuck as the policy through all these decades.

That bumpy ride effect is caused by cheaping out on the roadbed. Build a deeper roadbed and the slabs do not sink and frost heave. Basically you have to invest for durable infrastructure. We don't do that in MA. We underinvest to ensure perpetual repair work for the contractors.

 

[F-Line to Dudley]

That bumpy ride effect is caused by cheaping out on the roadbed. Build a deeper roadbed and the slabs do not sink and frost heave. Basically you have to invest for durable infrastructure. We don't do that in MA. We underinvest to ensure perpetual repair work for the contractors.

That's not totally it.

First of all, DOT's have also proven that the practice of estimating practical lifespans has little more science to it than throwing darts at a dartboard. We used to build all kinds of stuff with deep-set concrete all over the Northeast. But Northeastern DOT's continually under- and over-estimated actual lifespans at the extremes. Either it gets ripped up every 20 years for constant add-a-lanes or turning-lane augmentations and utility trenching and has to go because the base is too hacked-to-pieces, or has to absorb so many decades extra deferred maintenance that when it's finally shot you get stuff like 10 miles of simultaneous frost heaving on NY's Taconic State Parkway in winter 2015.

Its very durability and permanence mean you have to have some pretty good idea of what the next 30+ years holds for capacity management before doing concrete. And these next 30 years are a lot less certain than the last. "Inefficiency" thus has some degree of bizarro-efficiency sticking with materials that have finite time limit. It's not ideal, but it sorta works with how the Northeastern megalopolis is continually fidgeting with its roadways.



Second...it's got a lot to do with supply chain. Southern New England is a huge producer of blacktopping trap rock. There's quarries all over the damn place, especially within the first 5 miles inland of the CT shoreline the whole length of I-95. It is dirt-ass cheap and we've got another 100 years' supply left in most of the major quarries before we even flinch at the notion of "peak asphalt". Concrete is cheapest to produce in areas where there's more lime in the bedrock for producing Portland cement, the main ingredient. Northern New England is better for that than Southern New England, which is why Boston Sand & Gravel's source quarries are all located in Stafford County, NH. But places in the country that have very abundant lime deposits can locally produce it way cheaper. And it shows in the type of road construction they use.

For example, I was down in Orlando for about 4 days last month. The Everglades are one ginormous limestone deposit whose chemistry is built, mixed, and ultimately eaten by groundwater. They pave everything with regular blacktop, but every bridge from oldest/most-obsolete to newest is concrete...very few traditional steel girders. All bridge decks are concrete. All telephone poles everywhere are concrete...not just for the hurricane tolerances but also because they're cheap and easy to make out of recycled concrete (here you only see concrete poles for Metro Boston streetlights, not generic wire-carrying poles). All railroad ties and grade crossings are concrete. And they use jersey barriers for all kinds of off-the-wall purposes; they're like the proverbial Lego bricks of berms, fencing, and drainage channels. It's so stupidly cheap for them to mix cement locally they can gorge on it like we can gorge on local trap rock for below-cost blacktopping.

Same deal elsewhere. Got lots of old volcanic flood basalts laying around...you're gonna have abundant trap rock. Got an easy-to-acquire bitumen supply at home like we've got from parts of the Rockies and the huge deposits in Alberta...gonna have a very easy time transporting the petroleum ingredients that makes asphalt out of all that local bulk trap rock. Got limestone in abundance with shale...gonna have cheap Portland cement production capacity like the Great Lakes region, Gulf Coast, lower Plains, inland California, and other parts of the Rockies.

 

[tangent]

That bumpy ride effect is caused by cheaping out on the roadbed. Build a deeper roadbed and the slabs do not sink and frost heave. Basically you have to invest for durable infrastructure. We don't do that in MA. We underinvest to ensure perpetual repair work for the contractors.

I recall reading (many years ago) some discussion about how Germany (or perhaps it was another European country) specified a thicker asphalt and their roads required much less frequent repair.

I haven't heard any talk about our standard asphalt thickness lately. And the cost/benefit of going with a thicker layer. Anyone have any insight on asphalt thickness?

Given the cost of labor versus materials it seemed like a good idea to up the standard thickness of asphalt in order to stretch out the time between major repairs. Not to reduce the maintenance costs overall necessarily, because there is plenty of deferred maintenance on local roads where resources could be spent, but to give us better longer lasting roads in the meantime and create less transportation disruption do to the more frequent repair/maintenance needed.

 

[Scipio]

There is one street I can think of that uses concrete instead of asphalt: Babcock Street in Brookline. Does anyone know why Brookline went with concrete for that one road?

It's now in poor shape and deteriorating rapidly, you can see cracking and slabs sinking and rising throughout the entire road. I wonder if some of that poor condition is just the town's and their contractor's unfamiliarity with maintenance for concrete roads. The town pushed major work off for another year due to fighting over the bike facilities, but every alternative they have considered uses asphalt instead of putting down new concrete.

 

[JeffDowntown]

I recall reading (many years ago) some discussion about how Germany (or perhaps it was another European country) specified a thicker asphalt and their roads required much less frequent repair.

I haven't heard any talk about our standard asphalt thickness lately. And the cost/benefit of going with a thicker layer. Anyone have any insight on asphalt thickness?

Given the cost of labor versus materials it seemed like a good idea to up the standard thickness of asphalt in order to stretch out the time between major repairs. Not to reduce the maintenance costs overall necessarily, because there is plenty of deferred maintenance on local roads where resources could be spent, but to give us better longer lasting roads in the meantime and create less transportation disruption do to the more frequent repair/maintenance needed.

Germany uses not only thicker pavement, their roadbed standards under the pavement is about 2x as deep as US standards.

"But some of the most important differences between American and European expressways lie well beneath the surface. All highways are built by bulldozing softer subsoils and either tamping them or replacing them with more durable dirt or gravel. But in Germany the roadbeds tend to be 1.5 m or 1.8 m (5 ft. or 6 ft.) deep, twice the U.S. average. European engineers also devote more time and money to designing roadbeds that resist frost and have excellent drainage, addressing two problems that play havoc with U.S. thoroughfares. Each step, from laying the subsequent gravel or concrete layer to applying the asphalt surface, is taken with long-term durability in mind."

http://content.time.com/time/magazine/article/0,9171,159579,00.html

 

[choo]

HOV South station exit/ Logan HOV on 93 N coming into the city has a pretty nice bounce. that's concrete, probably not 7 feet of it though.

 

[mass88]

Germany uses not only thicker pavement, their roadbed standards under the pavement is about 2x as deep as US standards.

"But some of the most important differences between American and European expressways lie well beneath the surface. All highways are built by bulldozing softer subsoils and either tamping them or replacing them with more durable dirt or gravel. But in Germany the roadbeds tend to be 1.5 m or 1.8 m (5 ft. or 6 ft.) deep, twice the U.S. average. European engineers also devote more time and money to designing roadbeds that resist frost and have excellent drainage, addressing two problems that play havoc with U.S. thoroughfares. Each step, from laying the subsequent gravel or concrete layer to applying the asphalt surface, is taken with long-term durability in mind."

http://content.time.com/time/magazine/article/0,9171,159579,00.html

So why wouldn't MassDOT want to invest more time and money upfront and have roads that are stronger and last longer than what they currently do now?

 

[bakgwailo]

So why wouldn't MassDOT want to invest more time and money upfront and have roads that are stronger and last longer than what they currently do now?

I am sure some of it is politics - in that its easier to get/spend smaller sums more frequently then be able to get one big upfront cost/project funded, even if it would save money in the long term. Add in the jobs/contracts/etc to do the yearly paving, too.

 

[mass88]

Germany uses not only thicker pavement, their roadbed standards under the pavement is about 2x as deep as US standards.

"But some of the most important differences between American and European expressways lie well beneath the surface. All highways are built by bulldozing softer subsoils and either tamping them or replacing them with more durable dirt or gravel. But in Germany the roadbeds tend to be 1.5 m or 1.8 m (5 ft. or 6 ft.) deep, twice the U.S. average. European engineers also devote more time and money to designing roadbeds that resist frost and have excellent drainage, addressing two problems that play havoc with U.S. thoroughfares. Each step, from laying the subsequent gravel or concrete layer to applying the asphalt surface, is taken with long-term durability in mind."

http://content.time.com/time/magazine/article/0,9171,159579,00.html

I've never been to Germany, are their roads and infrastructure better than what we have in the US?

 

[davem]

I've never been to Germany, are their roads and infrastructure better than what we have in the US?

Unbelievably so. Our roads are downright embarrassing, and our public transit is a travesty compared to what they have going on.

 

[F-Line to Dudley]

HOV South station exit/ Logan HOV on 93 N coming into the city has a pretty nice bounce. that's concrete, probably not 7 feet of it though.

That's not concrete roadbed or the bare concrete decking, but some sort of concrete-mix coating poured on top then lightly etched by a pavement grinder. Used as an alternative to blacktopping that's more resistant to freeze-thaw on bridge decks and the steepest first few feet of tunnel inclines before the catch basins trap the flowing water. Usefully spreads out the pavement maint recycles on the calendar in hard-to-reach places like spaghetti ramps in the sky where most ramps are only 1 travel lane and not very easy to traffic-cone during a work shift.

All of the semi-related decks in/around South Bay constructed in the same early-00's timespan got it. It's not a bare concrete bridge deck because it's jointless and because it has been patched over the years (pan straight down in Street View and you can see outlines of filled potholes and utility cuts just like with asphalt). And it hasn't needed to be repaved yet like with asphalt because you can see the jersey barriers and drains are still perfectly flush with the original surface, never having been dug out and reset to a new surface.


The downside is obvious, though. It's a ROUGH ride because that etching is required for it to bond to the surface and trap/repel water above the seal. The vibrations get acutely uncomfortable for fingers on steering wheel if it's used for more than short stretches, so usage is generally limited to single-point targets like big sprawly ramp complexes. It's held up well over 12+ years, but MassDOT must have taken its fair share of driver complaints about the ride quality because they've avoided using it anywhere else.

Also, when it does have to get a full resurfacing it puts the lane out-of-commission many hours longer for drying/setting than asphalt...where you can pretty much drive on the top coat 20 minutes after the steamroller makes its final pass. So that's going to mean rotating weekends of full-on overnight shutdowns for each individual South Bay ramp they have to resurface when the time comes. I would guess they're just going to blacktop it next time since this type of surfacing never caught on.

 

[West]

Unbelievably so. Our roads are downright embarrassing, and our public transit is a travesty compared to what they have going on.

I can second this. I get to Germany about every third year or so, it's also a jolt even though I know it's coming.

This is even more true of Japan for the public transit. Roads are great in Japan, too, but especially regarding transit, the US / Japan contrast is even more shocking than the US / Germany contrast. I was in Japan this summer after a long time away and coming back to Boston felt like traveling from the first world to the third world. It's really depressing, we are just so incredibly half-assed by comparison. They must have a hard time keeping themselves from just laughing out loud in our faces.

 

[Arlington]

IIRC the German system requires builders to make guarantees of performance and durability (builder or a bondsman pays if the road fails early), so you pay a lot more for roads up front but the builder makes sure they last.

 

[bakgwailo]

I can second this. I get to Germany about every third year or so, it's also a jolt even though I know it's coming.

This is even more true of Japan for the public transit. Roads are great in Japan, too, but especially regarding transit, the US / Japan contrast is even more shocking than the US / Germany contrast. I was in Japan this summer after a long time away and coming back to Boston felt like traveling from the first world to the third world. It's really depressing, we are just so incredibly half-assed by comparison. They must have a hard time keeping themselves from just laughing out loud in our faces.

Yeah - pretty much this on the Japanese public transportation from local to regional rail is on an entirely different level from us. A friend of mine from Germany first visited Boston a few years ago, and took the Silver Line to South Station and then the Needham Line to Bellevue (where his now wife's parents live). He couldn't get over how ancient and medieval our commuter rail was - he said something to the effect of it being like what they had back when East and West Germany were still around.

 

[tangent]

I am sure some of it is politics - in that its easier to get/spend smaller sums more frequently then be able to get one big upfront cost/project funded, even if it would save money in the long term. Add in the jobs/contracts/etc to do the yearly paving, too.

The politics, if they were democratic (small d), would probably favor the less frequent better quality construction. The complaint I hear most often from friends and colleagues is about the disruption that road maintenance and construction causes. It really undermines the efficiency of the transportation system to be in what seems like a constant state of active repair/disrepair.

 

[tangent]

Germany uses not only thicker pavement, their roadbed standards under the pavement is about 2x as deep as US standards.

"But some of the most important differences between American and European expressways lie well beneath the surface. All highways are built by bulldozing softer subsoils and either tamping them or replacing them with more durable dirt or gravel. But in Germany the roadbeds tend to be 1.5 m or 1.8 m (5 ft. or 6 ft.) deep, twice the U.S. average. European engineers also devote more time and money to designing roadbeds that resist frost and have excellent drainage, addressing two problems that play havoc with U.S. thoroughfares. Each step, from laying the subsequent gravel or concrete layer to applying the asphalt surface, is taken with long-term durability in mind."

http://content.time.com/time/magazine/article/0,9171,159579,00.html

Thanks. That is what I thought I remembered... article from 2001.

Next question, what does it take to actually get construction standards improved to reduce maintenance costs and disruption? Federal, State, Local levels...

 

[F-Line to Dudley]

Thanks. That is what I thought I remembered... article from 2001.

Next question, what does it take to actually get construction standards improved to reduce maintenance costs and disruption? Federal, State, Local levels...

All that plus a sea change in practices. I highly recommend reading the "Ask me about being a Traffic Engineer!" thread on the somethingawful.com forums (free preview for 10 days every month; all other times it's paywalled). That's a long-running Q&A thread with a former ConnDOT traffic engineer. Very informative and often hilarious...easy enough for newbies and transpo geeks to grasp.

Basically..."But We've Always Done It This Way" mentality is 10x as entrenched on the highway side of most state DOT's compared to the more progressive transit and complete streets sides. Old capacity-expansion habits from the 1960's die hard, the long view is hard to stick to when shortcuts/cost-cutting/deferrals are too easy, and community input is a worse day-to-day terrorscape than what gets reported. Most of the examples are from wonderfully inept ConnDOT, but it's pretty much universal. And, yes...PLENTY of first-world foreign countries are equally dysfunctional when it comes to highway policy so there are plenty of warts to go around even with the ones at the high end of the competence scale. Entrenched archaic policy and practices abound when it comes to all things asphalt.

 

[mass88]

IIRC the German system requires builders to make guarantees of performance and durability (builder or a bondsman pays if the road fails early), so you pay a lot more for roads up front but the builder makes sure they last.

Why can't we have a system like this?

Another question (not sure if this has been discussed in the transit pitch threads) how much, a ballpark amount, would it take to completely modernize and expand the transit in the Greater Boston area to put in on the level of a London or a Tokyo?