Pouring Concrete Walk

[jwstewar]

Hadn't thought about the sand falling out from under the concrete. Wishing I had gone with the 2X4s now. The good news is I'm single handedly responsible for ending the drought here in Southern Ohio. My nice flat bed that I was digging out yesterday (hard as rocks from lack of rain) now looks like the bottom of a swamp. Guess I won't pour until next weekend. Now what can I do with the 2500 lbs of sand sitting on the truck and how do I get that trailer unhooked loaded down as well.......guess I'll unhook the trailer with a jack and unload the truck to the trailer even though I know that would be over 2 tons (it is only a little 5X8 cheapy from Lowes for hauling lawn mowers rated to haul a ton) but I won't move it just park it right beside the swamp err future walk.

 

[Green_in_MI]

I would go for the higher strength mix. 3500 psi won't get it done because that spec is an ideal number if you do everything else correctly. ie, water ratio, sand and gravel mix with the proper gradation, and good mixing mechanics. Portland cement can be purchased with a higher (5000 psi) rating

To get your sand properly compacted simply wet it lightly and tamp with a heavy flat object. You will need to a little experimentation and practice to get the right moisture content for full compaction. Too much moisture and you will see water squeezed out and too little you will see sand squeezed(pop) out. It's not rocket science you will recognize good compaction as you tamp on it.

Also the 3500psi is measured as a compressive strength and not a bending or flexural strength. That number would be about a third of the rated strength. Concrete fails in bending not compression. Its a small area so go for the higher strength mix especially if you ever think a heavy truck will drive over it. The 3500 mix might do if you use steel mesh approximately 1 inch above the bottom of the walk.

Don't overwork the surface because the fine material is rise to the top and become dusty over time.

 

[patrickg]

You can tamp stuff with a 4x4 pumped verticaly if you don't have access to automation. Regarding driving onto a walk... If it is located where it can be driven on or over, it will be, eventually.

Patrick

 

[Green_in_MI]

Pay no attention to my comment about Portland cement and psi rating. I was thinking of premixed bags I have seen at the big box stores. Everything else being equal, such as good aggregate and mixing etc, concrete strength is achieved mostly through water to cement ratios. Your bag of portland cement should have the mix ratios for desired strength on it. Also an item some people do not pay attention to is that the quality of water is important. If it is not clean and close to potable you probably will not get the good curing you want for strength. For your case an extra bag or so per yard will get you better results cheap.

 

[jwstewar]

OK guys, I finally got the sidewalk poured this past Saturday. What do ya think for my first attempt at finished concrete work?/w3tcompact/icons/cool.gif Only previous experience with concrete is dumping Quikrete in holes for fence posts or whatever. I did have a couple little problems that you'll see in some of the other pictures I'll post. It set up a little bit too much when I was trying to do the expansion joints, they got a little dry and didn't "smooth" out as quite as nice as I would have like and left little holes/rough spots. I zoomed in on these in the next few pictures. Is this something I should worry about? Should I put a concrete sealer on it? A mortor type mix? Obviously I don't want to bust this thing out and start over, but nor do I wants patches on a new sidewalk or have it cracking/crumbling come the first freeze.

Again thanks to all of you for the replies to help me tackle this.

Jim

 

[jwstewar]

A closeup.

 

[jwstewar]

Another close-up of an expansion joint.

 

[jwstewar]

A little bit farther view away, but straight on shot of a joint.

 

[jwstewar]

Another shot of one of my character flaws.

 

[jwstewar]

And yet another.