concrete mixing

The things Billy NY brought up got me to thinking more about your project. In my life I've hauled materials, mixed in a mixer or in a wheelbarrow, poured or shovelled into forms, and finished hundreds of yards of concrete, possibly more than a thousand. The first thing I'd say my experience has taught me is that the things Billy told you are not just excellent advice---they're crucial.

The most important thing you can do is find a place where you can do a practice pour. Otherwise, all the problems you encounter (and figure out how to deal with) are likely to wind up as visible defects in your sidewalk.

There are only three reasons I can think of that you would want to use pea gravel rather than crushed rock, and one of those (small portable concrete pumps require pea gravel and a six sack mix to be able to pump the concrete) doesn't apply in your case. The other two reasons are that you are planning an exposed aggregate finish and you don't know how to add the pea gravel to the surface only, or you have a large amount of pea gravel that you have to get rid of.

Talk to a cement products supplier in a masonry supply business, not a big box store, hardware store, lumber yard, etc. Also, try to talk to someone who's old enough to have used the products.

You'll constantly be tempted to use too much water. One of the things you can figure out in a practice pour is how not to. The order you put the materials into the mixer, the lowest angle you can run the mixer without spilling, getting all of the mud out of the mixer each time, etc. are things you don't want to be trying to work out while the first batch or two are setting up over there.

Get the finishing tools you'll need. Even the cheap tools Home Depot or Lowe's sells will get you through a few jobs, but you have to have them. There's no substitute for an edge finishing tool or a joint striking tool if you want the job to look professional.

Bill-KCKs whitewash formula might be quite a bit whiter than you had in mind, and whitewashing, as I remember, was something that had to be done regularly. Regardless of its durability, it gets dirty.

All the best, Stan

I do have a recipe for a White Portland Cement "whitewash" for concrete. It uses White Portland Cement, salt, lime, and water. This old stucco house has been "painted" with it for 53 years now. The stuff is tough. So you could use regular gray Portland and "whitewash" it with this "paint." Add in some sand for traction?

I'll scan the recipe and email it if you like.

Concrete contains lime as part of its base, as well as portland cement (bonding agent) and various sizes of aggregate, depending on what kind of mix design is being used. I'm not all that familiar with color specialties and concrete mix designs, but I would have to believe that a good masonry supplier should be able to provide the materials you need to achieve the color you desire.

To insure that you achieve that color, and because of all the work you intend to do by mixing by hand, it would be wise to create your mix design with help from the supplier, and then make a sample batch, making particular note of the quantities of each material used in your mix design, make it large enough so you can make a test pour (mock-up) and let it cure for 28 days to see if it achieves the color you want. You could vary your mix and make a few of these samples, but you must record the quantities of the materials used, by weight or volume, so that if you do achieve what you are looking for, you can expand the mix design for the actual pour which will be a much larger quantity of material. A mock-up provides you with the information you need, and is common practice for concrete and masonry finishes, to determine whether the finished result is acceptable, vs guessing. It also insures that you can or cannot achieve the desired result, prior to spending money on the complete job. I would also believe that what you are looking for is probably not complicated, fooling with the mix design and making a few test pours prior to ought to be a big help. The other thing I will add, but not totally necessary is that a sidewalk does need some abrasion resistance, and should be a strong mix design, keep your portland cement ratio high enough, and don't add too much water, you may want to change your stone aggregate to a crushed type, the irregular surface and texture of that kind of aggregate would seem to be a better choice, opposed to smooth round pea gravel, however that is also a matter of preference, material availability and or application, for a little used residential walkway it may not matter so much, but keep these kind of things in mind, that is a lot of hand work, strong mix design will last, a weak one, can spall easily, use care when finishing.. time for me to shut up now LOL !!!

best of luck, let us know how it turns out, especially the color.

• Lime in Concrete

I don't think lime will whiten concrete appreciably. Lime is one of the components of mortar, along with sand and Portland cement, and mortar isn't so much lighter than concrete mixed with the same materials that you'd necessarily notice it. I think what you want is white Portland cement. You can also buy white sand as long as money is no object.

All the best, Stan