concrete pouring?

[shapp]

Non- climbing related question. Need some advice. I have poured some slabs before, but not where they abut an asphalt street. I am replacing a 4 foot wide strip of gravel between my existing paved driveway and the asphalt street with concrete. How do I get a nice joint between the concrete and asphalt and how might you form this up for pouring it?

[Bronco]

Cut the asphalt with a saw and pour right up to it. No form between the concrete and asphalt.

[ketch]

What Bronco said. Just put a board and stakes on the sides of the drive if you are trying to match that line. Pour it right up to the asphalt. Oh and if yu want to match the asphalt order the concrete with lamp black and it will be real close in appearance.

[shapp]

So under this scenario I would run one end of the screed board on top of the edge of the old slab and the other screed board edge along the top of the asphalt cut edge?

[ketch]

That would be correct. If you are trying to match something like that. If it is going to have an interesting twist or slope than try to orient the board appropriatly.

[wayne]

You may want a slight lip above the street aspalt ;nail a atrip of ply to the asp and put a rounded edge trowel on it

[mattp]

That sounds suspiciously like you might know what you are talking about there, Wayne. Why the lip?

 

(I'd add to the above comments that he ought to be sure he prepares the ground underneath the new slab so that it will last longer by being sure it is heavily compacted. Forgive me if I state the obvious.)

[AlpineK]

I think you should gradually fill your entire yard up with concrete. Don't do any of this sissy prep stuff. Just dump it down and throw any metalic objects you were going to throw away such as pipes and bbq grills to stiffen up the mix. Then cover the entire thing with astroturf.

 

At least that's what the former owners of my house did.

[wayne]

I dont know the grades and slopes but it may prevent water from getting past the concrete and up? the driveway, it is to keep the wter flowing down the street

[Couloir]

This is a very good and, in my case, very relevant topic.

[Dechristo]

thickness of slab and reinforcement should be addressed for heavier vehicle traffic. Mattp has a good point on subgrade prep and compaction.

[shapp]

Thanks for the comments, stay on topic, which is dressing the edge of the concrete to the asphalt, I know all the other stuff.

 

P.S. there was no old slab where the new concrete will go, there is currently a 4 foot wide strip of gravel between my current driveway and the asphalt. I don't like it cause grass and weeds grow in there and it gets a little rutty from time to time.

[RuMR]

hey shapp...you might actually consider trapping a treated board edgewise between the two...there are several reasons, first: this will produce a square, monolithic piece of concrete, as opposed to the feathering effect of concrete poured against a ragged chunk of asphalt...this will prolong the life of that concrete edge.

 

Second: it will give a tire a slight roll point (don't know how to describe this) but being softer than either the ashpalt or the concrete it will let load smear across the two and prevent pounding down the asphalt as a tire goes from hard to soft.

 

Third: it looks nice and the concrete, if properly built, will long outlast that asphalt. When the time comes to repave the ashpalt you will have a nice premolded joint waiting for it!

 

fourth: concrete poured against ashpalt will interlock with the asphalt and you wind up tearing it (the asphalt) apart over time as they flex differently...

 

Or, you could say fuck it and pour right to the asphalt after cleaning up the edge and it will probably be ok as long as really heavy stuff doesn't routinely roll over it...

Edited April 14, 2006 by RuMR

[shapp]

My idea so far is to snap a line on the asphalt along the edge (the asphalt is not very thick along the edge) and carfully break as clean an edge as possible with a wide masonary chisel, did a test try and it works pretty good. Then butt up some of the fiber board expansion joint stuff to the asphalt edge and pin this in with some 6 inch spikes through the fiber board into the asphalt underlayment, then use asphalt caulking to run a bead where the fiber board meats the actual asphalt edge to make sure it is all clean and stuck so the asphalt will not chip away, then screw a half inch piece of wood to the top of the fiber board to run the screed board on top during pooring (taking off the wood strip after the concrete is set) to give that small lip as described above .

Edited April 14, 2006 by shapp

[Dechristo]

Before breaking the asphalt, better make a shallow saw-cut first as Bronco suggested or you'll end up with an uneven break-line on top.

 

The result will yield a rough surface below the depth of cut, but if the asphalt is thin, as you state, you can break the asphalt back below the saw-cut to allow the PT board or fiber expansion board (bad idea imo) a flat surface to marry to.

[shapp]

will use the PT board,

 

Do you think a dimand masonary/concrete circular saw blade on my old circular saw would be good enough or do I have to rent a regular concrete saw

[RuMR]

that should be fine...you will get a lot of tar on your saw though....i'd rent it and wreck their's!

[Dechristo]

a blade on a circular saw should do the job, unless it's a POS saw.

 

There are Carborundum blades made specifically for asphalt (cheaper). Iffen you can't find a couple, a segmented diamond-matrix concrete blade will work. You'll need to take time to allow it to cool intermittently after working the cut for a few minutes (and clean the blade of tar) else the blade may overheat and warp.

[Dechristo]

also, pick up a cheap can of clear lacquer and spray your chalk line before you start the cut; it'll keep your line on the asphalt while cutting.

[J_Kirby]

hey shapp...you might actually consider trapping a treated board edgewise between the two...there are several reasons, first: this will produce a square, monolithic piece of concrete, as opposed to the feathering effect of concrete poured against a ragged chunk of asphalt...this will prolong the life of that concrete edge.

 

Second: it will give a tire a slight roll point (don't know how to describe this) but being softer than either the ashpalt or the concrete it will let load smear across the two and prevent pounding down the asphalt as a tire goes from hard to soft.

 

Third: it looks nice and the concrete, if properly built, will long outlast that asphalt. When the time comes to repave the ashpalt you will have a nice premolded joint waiting for it!

 

fourth: concrete poured against ashpalt will interlock with the asphalt and you wind up tearing it (the asphalt) apart over time as they flex differently...

 

Or, you could say fuck it and pour right to the asphalt after cleaning up the edge and it will probably be ok as long as really heavy stuff doesn't routinely roll over it...

 

While a clean pour against a treated board is a good thing, some of these points are a little off. Keeping the pavement from “pounding down” needed to be done when the asphalt section was built, i.e. using adequate base rock and compaction. A treated board won’t perform any load transfer between the two materials.

 

The clean concrete joint is a definite plus for paving, though. Even a bad paver can match a nicely formed concrete edge.

 

There is no real interlock between the concrete and the asphalt to speak of. The asphalt edge will pull away from the concrete within a year or two and leave a small joint between the two. Whether this joint is a hairline or is wide open depends on what kind of climate and soil conditions are present.

 

One other plus of using a board between the two is the ease of cleaning up the inevitable slop over of concrete slurry onto the pavement next to the edge of the pour. A bit of sweeping will clean off the board while the pavement will show the concrete slop until it actually wears off the asphalt surface.

[Bronco]

I wonder what happened to Catturd? Isn't he supposed to chime in about six posts ago about the molecular structure of the concrete's elemental formularation in contrast to the soil compaction ratio per ashphualt's chemical reaction to a illegal millitant sexist pirate?

 

Was he finally banned?