Hardest concrete

Stan in Oly, WA

Well-known Member
I live in a neighborhood which has sidewalks which may be more than 50 years old. All throughout the area, the roots of trees in the planting strips have pushed up sidewalks, cracking them in some places, and causing sections to go out of alignment in others. In places where the misalignment is bad, people have tried using concrete to ramp up from the lower level to the higher. I have not yet seen this method be successful.

Is it possible to pour a concrete ramp, say 54" from side to side, and 12" wide (which could be more or less), by 1/2" to 3" thick, which wouldn't break up within a year? I'm almost certain that everyone in my neighborhood who has tried this has been an absolute novice. I've never seen any metal involved, and the idea of adding more cement or not mixing the concrete too wet probably never occurred to anyone. Still, I'd hate to try it and not have better results than what I've seen. I would be really embarrassed by that.

Thanks,

Stan
 
The material does have its limitations, this is one of them. the thicker part of it might hold awhile, but with all the things going on there, it won't be long term, regardless of the mix design. Eventually a new trip hazard will form when the thin end spalls off. I would think asphalt would be better, though messy with all the excess that will come off, loose aggregate etc.

20 years ago I was reading engineering news record and there was an article about the latest high strength concrete that was approaching 20,000 psi, might have been 19,000 psi. That is some unbelievable compressive strength, and I am not sure what application its used in, nor have I done any recent research on it but there is ultra high strength concrete which is now above the previous.

I don't think any of this material will perform at the same level if its thin like the end of a ramp.

Below links will provide lots of information, especially American Concrete Institute.

When I was in college, I did a research paper on concrete abrasiveness, got an A on it. I also spent a lot of time in the library reading ACI journals and information.

For highways, they would make trapezoid sections of concrete mix designs and place many different types in a circle, where a tire mounted on an arm simulated the wheel of a vehicle, it would run in circles for a specified time, then each individual slab would be evaluated to determine the most abrasion resistant design.
PCA

ACI
 
Thanks, Billy;

I was hoping you would weigh in on this. I guess I already knew what the answer was likely to be. I'm not a believer in miracles, or even in new products which use cutting edge jargon to give the hard realities a fast shuffle.

The City of Olympia has an interesting approach to dangerously pitched sidewalks: Once or twice a year a city engineering department employee comes by with a can of state of the art florescent orange spray paint and sprays the tripping hazards. It's not attractive, and it can't be of much use after dark, but it certainly is cost effective.

Stan
 
Is it possible to pour a concrete ramp, say 54" from side to side, and 12" wide (which could be more or less), by 1/2" to 3" thick, which wouldn't break up within a year?



HD-50 by Dayton Superior. It wont break up in your [b:276f917db1][i:276f917db1]lifetime[/i:276f917db1][/b:276f917db1] in sidewalk use. Its a dark product though so might want to epoxy it lighter after its done. It also sets up FAST so no fiddle farting around.

You cant feather edge it so you need to grinder it so its a mininum of 1/2 inch at the thinnest, but thats the road specs you might get away with it thinner for walking traffic. Pin it down (2 pins is fine) and bond break between the next piece of concrete. 54x12 ramped up to 3 inches is a 2 hour job.

The neighborhood kids will be ramping their bikes off it 45 minutes after you start dumping the bucket... its that fast. Its made for road work, a sidewalk is cake.

http://www.daytonsuperior.com/docs/default-source/tech-data-sheets/hd_50.pdf?sfvrsn=10
 
Why not just remove that 12" wide strip, then replace it with a piece 3" thick at one edge and 6" thick at the other edge?

Dusty
 
(quoted from post at 14:41:24 06/21/15) Is it possible to pour a concrete ramp, say 54" from side to side, and 12" wide (which could be more or less), by 1/2" to 3" thick, which wouldn't break up within a year?



HD-50 by Dayton Superior. It wont break up in your [b:f2968b8eb7][i:f2968b8eb7]lifetime[/i:f2968b8eb7][/b:f2968b8eb7] in sidewalk use. Its a dark product though so might want to epoxy it lighter after its done. It also sets up FAST so no fiddle farting around.

You cant feather edge it so you need to grinder it so its a mininum of 1/2 inch at the thinnest, but thats the road specs you might get away with it thinner for walking traffic. Pin it down (2 pins is fine) and bond break between the next piece of concrete. 54x12 ramped up to 3 inches is a 2 hour job.

The neighborhood kids will be ramping their bikes off it 45 minutes after you start dumping the bucket... its that fast. Its made for road work, a sidewalk is cake.

http://www.daytonsuperior.com/docs/default-source/tech-data-sheets/hd_50.pdf?sfvrsn=10

Thanks Rich, good to know about
 
That may be true in an absolute sense, but I wouldn't have that much trouble accepting a relatively simple solution that would buy another ten years. In any case, the tree is on my neighbor's property, and the roots are lifting the sidewalk in front of my property. Cutting into the embankment for new front steps to the street a few years back, I ran into large roots from the same maple tree forty feet from it. Got to admire its survivalist tendencies.

Stan
 
That is really interesting, I've got a garage floor slab, that I don't believe was the best quality job, given the aggregate type that was exposed and the finish on it, which has eroded over the years, its rough only where a vehicle is parked. If this material can be used to fill, might be a good fix, vs demolition and pouring new. I wonder if it can be used like that?
 
(quoted from post at 18:29:35 06/22/15) That is really interesting, I've got a garage floor slab, that I don't believe was the best quality job, given the aggregate type that was exposed and the finish on it, which has eroded over the years, its rough only where a vehicle is parked. If this material can be used to fill, might be a good fix, vs demolition and pouring new. I wonder if it can be used like that?

It will work.

It works best if you cut the edge and use a chipping hammer to get it down 1/2 inch. Thats how I do it, square up the area with a skill saw and diamond blade (with water). Use a Bosch Bulldog chipping hammer to drop the patch area down. Mix it up according to the directions and WORK FAST. It does not finish nice or smooth, usually the first screeding or troweling is the best, it seems to get worse the more you work it but that could be just frustration after being used to concrete. Slap it like a beaver slapps his tail, give it a little puddling action and QUIT TOUCHING IT. Thats the hardest part, stop trying to make it perfect, it wont be, its for a road afterall. Its like spreading roofing tar but it will kind of self level if you mix it a little loose. Dont bother with a finish trowel, it wont work well, it just pulls the mix all around and makes you mad. A margin trowel is all thats needed (or wanted). If you are watching it, when it gets hot, the top starts skinning over, thats about your best time to smooth it out without it sticking to you. It dont take long to get to this point, 20 minutes tops and depending on outside temp, could be 5 or 6 minutes. Did I say it sets up fast? Keep moving...

If the end result is rougher than you care for, you can smooth it down with a surface grinder but like concrete, you will end up with some exposed aggregate.

You CAN patch areas thinner than 1/2 inch but they can break out, its hard but brittle when its thin. If a little area chipps out, mix a part coffee can and patch it again...

Try a bag, its good stuff. Its everything Thorocrete wanted to be but failed at. The most common complaint is its too dark and the patch dont match the sidewalk. And it is dark, charcoal gray but if you weed sprayer it and keep it wet as it gets hot, it tones that down a little.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top