Question re: asphalt vs. concrete

[nickbeaulieu]

Hey all,

I was wondering if anyone could tell me what the deciding factor is in using asphalt vs concrete for sidewalks and curbs.

There are a few road projects going on on the route to work for me. One is near my home. They're building bus stop pads, and they're using asphalt for them. There's one spot that has a pad on each side of the road, and one side has a concrete curb and the other has an asphalt curb.

The other spot they're doing work is the road connecting the south fraser perimeter road and king george near the pattullo bridge. The sidewalks are all concrete, but they've also got bike lanes, and these are asphalt.

So aside from cost, and ease of installation is there a reason to use asphalt over concrete?

[M00dy]

Originally Posted by nickbeaulieu

Hey all,

I was wondering if anyone could tell me what the deciding factor is in using asphalt vs concrete for sidewalks and curbs.

There are a few road projects going on on the route to work for me. One is near my home. They're building bus stop pads, and they're using asphalt for them. There's one spot that has a pad on each side of the road, and one side has a concrete curb and the other has an asphalt curb.

The other spot they're doing work is the road connecting the south fraser perimeter road and king george near the pattullo bridge. The sidewalks are all concrete, but they've also got bike lanes, and these are asphalt.

So aside from cost, and ease of installation is there a reason to use asphalt over concrete?

Generally speaking concrete is more expensive to install, but it lasts longer. Asphalt is often a smoother running surface and generally quieter wheel noise too for roads.

Bus pads at busy bus stops are typically concrete as buses have some of the highest axle loadings on the road, & starting/stopping creates a lot of wear & tear.

[nickbeaulieu]

Originally Posted by M00dy

Generally speaking concrete is more expensive to install, but it lasts longer. Asphalt is often a smoother running surface and generally quieter wheel noise too for roads.

Bus pads at busy bus stops are typically concrete as buses have some of the highest axle loadings on the road, & starting/stopping creates a lot of wear & tear.

Ya, but what I'm referring to is for sidewalks. Most sidewalks I see are concrete. and the Bus pads are where the people stand.. again, I usually see them as concrete.

[M00dy]

Originally Posted by nickbeaulieu

Ya, but what I'm referring to is for sidewalks. Most sidewalks I see are concrete. and the Bus pads are where the people stand.. again, I usually see them as concrete.

Bus pads are highly durable areas of the roadway surface at bus stops, usually constructed in concrete, addressing the common issue of asphalt distortion at bus stops.

https://nacto.org/publication/transi...ents/bus-pads/

Similar principles apply to sidewalks too. Concrete is more durable.

Another factor is that typical asphalt placing equipment (gravel trucks, spreader, rollers, etc) are generally sized for roads, so if you were to hand-place sidewalks it's more of a hand-finished job & so more likely to have flat/level/true issues than machine-placed. Concrete doesn't have this problem & also specialized equipment exists for slip-form curbing, etc.

[VancouverOfTheFuture]

Originally Posted by nickbeaulieu

Ya, but what I'm referring to is for sidewalks. Most sidewalks I see are concrete. and the Bus pads are where the people stand.. again, I usually see them as concrete.

generally asphalt is only used for cubs and sidewalks as a temporary thing. i.e. we need it now ASAP and we can finish it later. it requires a lot more planning and work then asphalt.

bike lanes as asphalt for the same reason as driving lanes; cheaper & smoother. plus by using a different material it helps differentiate what the pedestrian realm is and what that bike realm is.

sidewalks go concrete because the idea is they never get changed or worn out and allow a texture to be added for extra grip and drainage. you can kind of change the groves/texture to what you want compared to asphalt being what it is. you can even see the different textures from the different decades. i.e. the 1950s was very different then before or after. look at Shaughnessy and Point Grey; many are 80-100yrs old and still in quite good shape. plus, utilities don't run under sidewalks, they go under roads, or in some cases back lanes (rare).

on roads, concrete lasts longer, see Point Grey as a perfect example; the municipality used concrete exclusively and tons of roads are still in existence. but it is louder when cars go over due to the expansion joints as well as it is much more expensive to repair utilities that run under them.

an example, to dig down into asphalt, you take a pick axe and hack away, then to repair it, you smoosh down some new asphalt. takes 2 guys a few mins, and it is read to be driven over immediately. for concrete to be repaired properly, the hole needs to be squared out and cut at the proper angles so the patch doesn't pop out with frost, ground movement, etc. then concrete needs to be pour in, smoothed, groved, and then it isn't derivable until pretty much fully cured; ideally 1 day it would need to be coned off at the minimum.

another aspect that a lot of people don't think about is that roads are a financial asset on the balance sheet, and the way cities account for them are different with asphalt vs concrete. concrete is worth a butt load more on the balance sheet, and it is depreciated over a longer term. hey that's good right? yes, but, when they get a hole in them, like the utility example above, they end up almost worthless. they take a huge huge financial hit on the balance sheet when opened up; even when repaired properly. compare that to asphalt, it is not worth much on the balance sheet, but an easily patched hole does almost nothing to the value of that road.


hopefully that helps a little with your question.

Originally Posted by M00dy

Another factor is that typical asphalt placing equipment (gravel trucks, spreader, rollers, etc) are generally sized for roads, so if you were to hand-place sidewalks it's more of a hand-finished job & so more likely to have flat/level/true issues than machine-placed. Concrete doesn't have this problem & also specialized equipment exists for slip-form curbing, etc.

expanding on this, look at #3 Rd in Richmond, all the bike lane asphalt had to be levelled by hand, and it is incredibly bumpy because of that.

[libtard]

It's funny how Vancouver metro is dead set against using concrete for roadways. There are still remnants of old concrete surfaces on Granville and grant mconachy Way. They're old and terrible though. NEW concrete surfaces that have been diamond grinded are the smoothest, and longest lasting surfaces available for roadways but they're expensive and frankly too profressive and high tech for Vancouver.

[nickbeaulieu]

Originally Posted by M00dy

https://nacto.org/publication/transi...ents/bus-pads/

Similar principles apply to sidewalks too. Concrete is more durable.

Another factor is that typical asphalt placing equipment (gravel trucks, spreader, rollers, etc) are generally sized for roads, so if you were to hand-place sidewalks it's more of a hand-finished job & so more likely to have flat/level/true issues than machine-placed. Concrete doesn't have this problem & also specialized equipment exists for slip-form curbing, etc.

Thanks for the link. These bus pads (and the area where the pedestrians stand) are being done in asphalt. They're already done, actually. They're for community buses, so that could explain the choice of using asphalt over concrete.

Thanks for the explanation, VancouverOfTheFuture. That was pretty much what my guess was, the more temporary aspect of it all. I get the feeling that, from where they're installing these, they'll be changed sooner rather than later as the area is developed.

[CanSpice]

Originally Posted by nickbeaulieu

Thanks for the link. These bus pads (and the area where the pedestrians stand) are being done in asphalt. They're already done, actually. They're for community buses, so that could explain the choice of using asphalt over concrete.

Thanks for the explanation, VancouverOfTheFuture. That was pretty much what my guess was, the more temporary aspect of it all. I get the feeling that, from where they're installing these, they'll be changed sooner rather than later as the area is developed.

They could also be temporary. New West was adding a sidewalk somewhere in Queensborough over the summer, but they only had the budget in the current year for asphalt. It'll eventually be replaced with longer-lasting concrete.

Edit: actually that's just what you were saying, never mind me

[M00dy]

Originally Posted by nickbeaulieu

Thanks for the link. These bus pads (and the area where the pedestrians stand) are being done in asphalt. They're already done, actually. They're for community buses, so that could explain the choice of using asphalt over concrete.

Thanks for the explanation, VancouverOfTheFuture. That was pretty much what my guess was, the more temporary aspect of it all. I get the feeling that, from where they're installing these, they'll be changed sooner rather than later as the area is developed.

I think most community bus stops are just in the asphalt roadway. It's typically bus loops & other high traffic areas that they put in concrete pads.

[aberdeen5698]

Originally Posted by libtard

It's funny how Vancouver metro is dead set against using concrete for roadways.

There are utilities under almost all of those roads that require access from time to time. Concrete makes such access very difficult and expensive.

[Stingray2004]

When a developer engages in residential land development, for example, the applicable municipality always has by-laws establishing design and construction standards for sidewalks, curbs, etc. Becomes more complex in terms of specific zoning applied thereto but the civil engineering firm retained by the developer takes care of these detailed matters.

Virtually all Metro Van municipalities require concrete curbs/sidewalks.

Asphalt pavement can be used for meandering trails, etc. within said residential development. Again, depends upon specific municipal by-laws.

As for bus stops, I have noticed that, along Oak St. in Van City for example, all bus stops are situate upon concrete slab. Since buses are quite heavy vehicles and frequently utilize bus stops along that corridor, if asphalt pavement was utilized considerable rutting would occur - esp. during hot summer months. Van City might also have a by-law dealing with this matter.

Finally, in terms of utilizing concrete pavement on roadways - a good portion of inner Van City roads originally utilized concrete pavement (back in the day) and many sections are still utilized while most others have been paved over with asphalt. Hell, even as late as circa 1970, Van City proper utilized concrete pavement when rebuilding a residential street in front of my gramp's house - suspect that was an anomaly then though.

Between circa 1966 - 1968 both the BC government as well as the feds utilized concrete pavement for the following 4-laners:

1. Gaglardi Way to SFU;

2. SW Marine Drive to UBC;

3. Grant McConachie Way to YVR - footnote: it was constructed all the way to the Moray Bridge but when the Arthur Laing Bridge opened circa 1974 a considerable portion was removed (after only 5 - 6 years) due to the new alignment;

PS. Obviously - concrete pavement is considerably more expensive than asphalt, upfront, albeit concrete pavement has a longer life-cycle.

[harryc]

Originally Posted by VancouverOfTheFuture

generally asphalt is only used for cubs and sidewalks ,,,anip....

Thank you for the explanations and insights - down here outside of Chicago we have 2 other options :
A thin layer of asphalt over the old concrete/brick road, resurfacing involves a big specialized machine that grinds up the old asphalt - remixes and re-vitrifies (?) it on the spot - and then lays down a fresh thin layer. Very nice smooth roads.
Brick ! easier for those utility digs (once you have a few crews that can deal with it) and it is water permeable reducing the runoff (which we handle in sewers, tunnels, and reservoirs). Plus it is what many of the streets are still made of.

[VancouverOfTheFuture]

Originally Posted by harryc

Thank you for the explanations and insights - down here outside of Chicago we have 2 other options :
A thin layer of asphalt over the old concrete/brick road, resurfacing involves a big specialized machine that grinds up the old asphalt - remixes and re-vitrifies (?) it on the spot - and then lays down a fresh thin layer. Very nice smooth roads.
Brick ! easier for those utility digs (once you have a few crews that can deal with it) and it is water permeable reducing the runoff (which we handle in sewers, tunnels, and reservoirs). Plus it is what many of the streets are still made of.

some roads in Vancouver do have asphalt over old concrete roads, easiest way to tell is when there are evenly spaced cracks in the asphalt layer and the gutter part of the concrete curb is not visible. we also have some over brick roads in very, very few places in Point Grey, Strathcona, Downtown. that is extremely rare and in some cases the old brick has never been paved over.

i don't think that the CoV currently cares much about its brick roads as in Gastown, they put brick down in the 1970s as a way to revitalize the area and it is now nothing but patches of asphalt in all the brick since they don't maintain it or fix it with brick when they do open it up.

a city as old as Chicago must have some interesting old infrastructure still poking out in places I'd imagine; both above and below the ground.

[nickbeaulieu]

I have another question regarding the process of lay asphalt.

They're repaving Bridgeview Dr. in Surrey and widening it. They seem to be almost done, however I see that the asphalt they've layed is a good inch or two below the edge of the concrete curbs.

Do they do another layer of asphalt at the very end of the project so this is level?

[M00dy]

Originally Posted by nickbeaulieu

I have another question regarding the process of lay asphalt.

They're repaving Bridgeview Dr. in Surrey and widening it. They seem to be almost done, however I see that the asphalt they've layed is a good inch or two below the edge of the concrete curbs.

Do they do another layer of asphalt at the very end of the project so this is level?

Yes, that's standard practice for many projects. Place bottom lift & use that as the running surface until you're ~done the project. Then place final lift immediately before completion so no deficiencies develop before you hand over.

[VancouverOfTheFuture]

Originally Posted by M00dy

Yes, that's standard practice for many projects. Place bottom lift & use that as the running surface until you're ~done the project. Then place final lift immediately before completion so no deficiencies develop before you hand over.

although i know of a few places that still need that final level, and it has been many years since the end of the project. i never understood how that could happen, someone must inspect the finished project.

[nickbeaulieu]

Originally Posted by M00dy

Yes, that's standard practice for many projects. Place bottom lift & use that as the running surface until you're ~done the project. Then place final lift immediately before completion so no deficiencies develop before you hand over.

Cool, thanks

[M00dy]

Originally Posted by VancouverOfTheFuture

although i know of a few places that still need that final level, and it has been many years since the end of the project. i never understood how that could happen, someone must inspect the finished project.

The Fremont Village development in Poco has been on bottom lift for years now. If i recall correctly, they just actually had to mill & re-pave sections of it because it had degraded & rutted/potholed so bad.

It's a smart method for medium term delays, but bottom lift mixes aren't intended to be driven on so it doesn't work forever.