I am trying to build an exposed aggregate concrete walkway joined to an existing driveway. The driveway slopes on one angle, and the walkway will have to share that slope as well as slope(on another plane) away from the house. I am trying to figure out the best way to make this look great. I would love to find a site with directions, and especially pictures. Any suggestions on the whole project as well as websites?
concrete walkway project
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machmeter62
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jmt1271 said:
To gain experience, I would buy or get a thin sheet of masonite at a building supply. It's inexpensive. Cut a 3.5" piece off the 4' or 8' length, unless you already have some. Bend it in a complete circle off the 4' end or 8' length, and fasten the ends together with nails or screws with adequate overlap. Get small bags of ready mix to test your skills! Pour the mixed ready mix into your circle form, on a hard surface, let it set up for a little while based on temperature. You also don't want "too loose" of concrete. Seed the aggregate, grade it level to your form. Don't trowel below the surface if you want to walk barefoot on it? Again, let it set up longer this time because you will be exposing the aggregate with a garden house! Go with very lightly spraying at surface level, barely exposing the aggregate! As it starts to dry harder, and you want more exposure, spray lightly again. It may take you several tries, but the knowledge builds fast. If you are doing it by yourself on the sidewalk, I would just try one section per expansion joint, until the confidence builds? Also those round practice slabs won't go to waste; they can be used in gardens, etc. You can practice with different amounts of seeding for your satisfaction. Hope this helps?
machmeter62
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JMT1271: You can also use the remaining masonite for special turns for landscaping purposes, etc. on your new sidewalk? Use adequate stakes so it doesn't deform however!!
Not having a lot of luck looking for step by step directions online. From what I gather, I basically need to just keep working the forms until they are right and then go to town, right? One end is lower than the other, should I start the pour on the low end and go to the high end?
machmeter62
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You may want to invest in a good masonary book from Home Depot or Lowes; the books include a lot of expert advice.jmt1271 said:
I would set the mixer up at a convenient location, and decide from there; the start and finish point to make it easy on yourself, the slope shouldn't be a factor. Are you mixing the concrete, or is this a redi-mix truck? Transporting concrete is a back breaking job with a wheelbarrow! Also I would recommend some 3/8" rebar for added strength!
How long and wide will the sidewalk be? Is the pour going to be done completely in one day? Slope on the side for rain runoff can be 1/4" per foot to prevent standing water.
crbr
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jmt1271 said:
$0.02
There's a little more to this than meets the eye.
I worked for a life-long concrete / brick mason for a few summers during college. I learned a few tips from him that have never failed me with exposed aggregate finishes.
Tip of most importance (in my opinion) is predicting (planning) the finish.
That said, once the forms are erected and if you plan on having any horizontal surfaces to be exposed, spray the face of the form with a curing retardant (not a curing sealer). Use the retardant on the surface and the forms. Spray the forms as close to time before the concrete hits them so that it doesn't dry on the form.
Also upon finishing the placement, place your expansion joints while wet. Once you have the surface finished, spray the retardant on the surface. Spray liberally.
This allows the subsurface to hydrate to a point of a more solid mass, leaving the surface in a retarded condition, allowing for the water to remove the surface concrete, exposing the aggregate. Spray lightly until you get a feel for the exposure.
Predicting ahead is the key. Know your humidity and temps and anticipate a slow or faster hydration process. Once it goes, you should be ready to spray the surface.
As the other poster stated, practice would be beneficial but every day will be different in conditions for hydration.
Know in advance that you will want the subsurface to set a bit more than what the surface will appear to be set (with the retardant chemical). Without the retardant, you'll get a portion of the aggregate exposed properly and the rest of the placement will set up.
And again, spray the horizontal form surfaces as well, for the same useful methodology and concluding results. Took me the better part of three summers of work to get this down to a practice.
It's not difficult, by just knowing what you have pre-planned with use of a retardant. It won't hurt the concrete and will assist in slowing the evaporation of moisture, which is a good thing.
Your mileage may vary. Others here will have different opinions but this has worked well for me over the years.
machmeter62 said:
I will be having a truck deliver around 3 yds, plus a little since you never get it all out of the truck. The dimensions are 50 ft long by 4 ft wide. There will be radiused turns on both ends with straight sides. I wasnt intending on reinforcing the crete as it is just for foot traffic. My current problem is trying to figure out just how level the bottom surface(under the crete) needs to be. I wanted to maintain 4" thickness throughout, but the lay of the land makes me want to consider allowing it to vary between 3" and 4" to minimize ground prep. Is this okay?
Bigboyskioti
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Reinfore it! Foot traffic won't break it the shifting of the ground will! Rebar won't stop it from breaking it'll keep it together. My opinion is 2 bars the entire length with some from side to side, about every 3' apart. make the rebar look like train tracks with crossties. Either way it's a must.
machmeter62
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jmt1271 said:
If you are having a redi-mix truck deliver 3 yds of concrete; they will not pour the concrete out of the truck at your convenience without holding financial costs! You will need experienced help for a nice job too; or the following week you will be renting a "jackhammer" and starting the project over!! The seeding, expansion joints, and finishing job requires extra time too, and doing the job solo will result in a disaster; this is my opinion only!
The thickness can vary, depending on the compaction of the soil. Rebar will help prevent cracking there, and how much future weight may go on the walkway?