Quote:
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.
Quote:
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.