what could possibly have gone wrong? this past weekend I patched a
couple spots in my driveway with Sakrete brand cold patch, exactly per
directions - one "hole" was actually just an asphalt skin that had
peeled up, a couple other spots I needed to dig away all the old rotten
asphalt all the way to the base, in those cases I dug all the base up,
screened the gravel out, made a new gravel base, and finished with about
1.5" to 2" of cold patch (deeper than the asphalt that was there
before!) I used it exactly per directions, squared the edges of all
holes, never put it down less than 1" or more than 4" thick, tamped it
by hand with a 8" square steel tamper until it wouldn't compress down
any more. After a day or so it was mostly hard so I figured all was
good. Today I came home from work and it is SOFT! Not sure why, except
it was up to about 80 degrees, but it is cool and rainy now. It still
won't tamp down any more, but if I just touch it with my hand and push
laterally, it moves like there's next to no adhesion at all. What the
heck do I do now? I was hoping that I could seal the driveway later
this summer, but if these patches don't work, what's the point?
replace "roosters" with "cox" to reply.
You might try putting a steel plate or thick plywood sheet over the patch
and driving your car or truck(heavier the better) over it to compress the
patch.You'll get more pressure that way.
It's probably soft because the volatiles in the material BELOW the surface
have not dissipated yet,and the 80 degF heat causes more volatiles to
evaporate and soften the surface material.
describe the pressure which is force divided by area.
The pressure exerted by the tire on the road has to equal or be less than the
air pressure in the tire. Any other condition would be a bad day (flat tire).
About 30 pounds per square inch, although here it was recommended to
put a plate or plywood sheet over the patch, so the weight would be
spread out more.
I have no idea how much hand tamping does, but it's spread out too to
8 inches square, he said.
We have a lot of holes in our n'hood too. Does this cold patch work
pretty well most of the time. I saw a car recommended for when one
has no tamper. Is that good enough or, when I pull away, will the
black stuff go up on my fender and stick there?
Yup, about the tire pressure and that is the key. The weight of the vehicle
is less of a concern than the tire pressure. Although a heavier vehicle
would give a larger contact area for a given tire pressure.
Well, not exactly. Let's say you have 40 psi in the typical car tyre.
Making that 100 psi (if the tyre does not pop) and you would likely have
very little difference in contact area because the tyre shape is determined
by the tyre pressure and the tyre construction. Even with no pressure in
the tyre there will be pressure on the surface. So while pressure is part of
the game, it is not the only and maybe not even the principle player.
The standard method is to place a board or steel plate over the patch
and drive a car or truck over it. In that case tyre pressure makes zero
then we will have approximately 500/40 = 12.5 square inches of contact
area. If the tire pressure is increased to 100 psi then there will be
approximately 5 square inches of contact area. Rubber deformation is not
accounted for in these calculations and that is why the number is
approximate. Of course rubber carries very little of the load.
Now a reduction in contact area of 60% may not be much to you but to me it
is significant. Air pressure is the significant factor in assessing the
pressure exerted by a tire on the ground. If it wasn't the significant
factor then some other component would have to carry the weight of the car.
What do you propose that component to be? The tire sidewall?
a FWD auto usually has approximately 60-40 weight distribution,front to
that's 1800 lbs for the front wheels,divide by two,and you get 900 lbs
pressure on the plate.Since you slightly crowned the cold patch,all that
pressure is compressing it. The plate is to give an even distribution of
pressure on the patch,since the tire contact patch will deflect with the
uneven surface of the patch.
And you can leave that pressure ON the patch as long as you want,while a
tamper gives only a brief pressure.
Well, it's still soft... it's definitely the sun doing it. It's *way*
soft today, with the sun shining on the stuff, while yesterday it was
only "kinda" soft... Sakrete has not responded to my inquiry. Any
ideas what to do now? This is the only brand of cold patch I've been
able to find locally. It's been a full week since applying the patch.
replace "roosters" with "cox" to reply.
I had the same problem with a product from quickcrete. I ended up calling and
asking why there product was doing this? They told me it still had moister in it
And throwing dry sand on it would draw out the moister! Then I had to wait 28
days before putting a sealer on it. Did you ever fix what was wrong?
On Friday, August 8, 2014 9:44:01 AM UTC-4, Kris wrote:
sold the house a few years ago, so I can't give a long term report. But th
e patches did eventually firm up. Company never did reply to my inquiry bu
t after a long time they did set and we were able to seal the driveway so i
t looked pretty good. Not as good as a proper mill and repave, but good en
ough that it didn't look as awful as it did when we first moved in, which w
as the goal.
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