Does anyone know how to make cement with dirt? I remember reading about it somewhere. The person just remembered using it back in the 30's I think. But offered no information on how to do this. I have lots of unlevel yard. Thought this would be perfect idea to use since our sidewalk outfront needs to be replaced, insurance reasons. And, don't have the money for a new sidewalk. Any suggestions please!? Thankyou.

-- darlene bachovin (www.winterlove@theglobe.com), February 25, 2000

Answers

Concrete is made of Portland cement, water, and aggregate. The aggregate has a great deal to do with the quality of the finished product. Any "filler" can be used, including "dirt", wood chips, sawdust, peach pits, or precious gems. I suspect that you are flirting with false economy. "Dirt" contains organic material, and it's use will result in very inferior concrete. What you really want is a good quality concrete with both large and small (inorganic) aggregate - big and little chunks of sound sand and rock. For a sidewalk, something on the order of "1/2" minus", that is to say the largest "chunks" are about 1/2". You can do this yourself by hand (MUCH work), with an electric mixer (definately under the heading of physical labor), or you can have it delivered already mixed. You'll save a little money with either of the first 2 (Do NOT buy "sackcrete" or similar products - aggregate and cement in the same bag. This is convenient, but way too expensive for any but the smallest jobs.) However, check out the prices for delivered concrete. It may be a lot less than you suspect. The big savings in installing a new sidewalk are in doing the construction yourself, and that should be substantial. Good Luck! Brad

-- Brad (homefixer@mix-net.net), February 25, 2000.

Darlene, do you remember just what was being made out of this dirt concrete? Typically you want to avoid getting organics (dirt) in concrete or mortar. Organic matter interfers with the chemical reaction that takes place in the setting concrete/mortar. Organic matter is less strong (more compressable) and subject to decomposition if exposed to air and or chemicals. Either of which will weaken the concrete/mortar.

There is, of course, adobe, and similar mixtures. They are clay mixed typically with straw. It is also possible to make a mortar-type product by mixing a clay with water to a thick slurry consistency. But this would be more for chinking a log or stone structure and the life expectency would vary greatly in differing climates.

If your sidewalk is the the typical sort made of squares, is it possible to repair what you have to gain some time? Sometimes you can dig out the slabs, level the ground underneath them and re-lay the slabs. A broken corner could be removed and repoured using Quik-crete. A slab broken in half could be lifted, the ground leveled, the slab replaced, the broken edges chisled away, and Quik-crete or another repair cement/mortar could be used to fill the gap.

There are a lot of books at the library that will tell you either how to repair or repour concrete. You may be able to find a commercial repair person who will work with you-letting you break out and remove the old sidewalk, digging and starting the leveling/packing needed for the new sidewalk. Lot of work though.

I'd be very interested in knowing more about what you read if you can remember anything else. Gerbil

-- Gerbil (ima_gerbil@hotmail.com), February 25, 2000.

Darlene: I think what your'e looking for is info on rammed earth construction, usually used to make walls. There are several variables here that need to be considered. The first is soil type. You definitely do not want organic material in it for reasons stated by others. The second is weather conditions locally. If there is alot of rain it might not be a good idea, however if you decide to go ahead with it, here is how I would do it.

Get ready for alot of hard work. First, remove top soil to get down to non-organic sub-soil. If you want the slab to be 4"thick, remove the first 4" of subsoil, then rototill in 10-15% portland cement as a soil stabilizer. This will fluff the soil. Moisten the subsoil before you do the tilling. Try to assure that it is evenly moistened. The soil should be moist enuf to make a ball in your fist but not so wet that water runs out between your fingers. Rent a plate type compactor and compact what you've done. You should have at least a 50% volume reduction from the compacting. You'll be able to tell when its been compacted enuf just by the way it feels and sounds. Repeat the process with the second layer, but do the tilling and mixing outside of the new sidewalk area. It might not be a bad idea to use some type of reinforcing wire (old fencing would work i think) between the layers. Also, especially if you get a fair amount of rain, put a slight crown in the middle so the rain will not puddle and will run off. Good luck.

-- john leake (natlivent@pcpros.net), February 25, 2000.

Darlene...this isn't fair to the other responders 'cause I'm a civil engineer - I think what you have heard about is called "soil cement". It is used in construction, often as a backfill above pipelines which run down hillsides and which need to be erosion resistant. It is also sometimes used under roadbeds. There is no set recipe, you can use say 3% minimum portland cement up to say 20% P cement by dry weight....obviously the greater the cement contact the harder / stronger the final result....mix ingredients dry, then either add water & mix, or place dry and sprinkle...in your case I'd suggest mix "wet" (just damp, not soupy). Do try to keep the dirt "clean".

All said & done, I'm not sure you'll save much $$ over just putting in a 4" PCC walk.

I agree that you should do something, tho, if its a tripping hazard, both from an ethical perspective as well as (possible) legal consequences...

Which reminds me, your City may want you to get a permit (if you're caught)....some cities have crews which will place cold asphatic- cement-concrete at tripping hazards like raised sidewalks from trees...

-- Guy Winton (guyiii@home.com), February 25, 2000.

Just a comment. I don't know what the costs of cement (not concrete) and aggregate are in your area, but here, where portland cement costs almost $7.00 per 94 pound bag, and pre-mixed aggregate costs only $17 per 3000 pounds, I'd be very reluctant to put the expensive cement into a product which will be so inferior to actual concrete. I mix five or six parts aggregate to one part cement, depending what I'm making. So the main part of the concrete is the cement, not the aggregate. Another way to put it: if you buy redimixed concrete by the cement truck, they use five bags of cement per yard of concrete for most jobs (six bags if you have to pump it). This translates to $35 worth of cement to $17 worth of aggregate, approximately. Unless you are very destitute, it may be that you are being penny wise and poung foolish.

I have a philosophy about building things, and maybe life in general. Five years from now, you will not be thankful for the money or time you saved by doing a job in an manner less perfect than you wanted; you'll be kicking yourself for not doing it the way you knew was right the first time.

-- jumpoff joe (jumpoff@echoweb.net), February 26, 2000.

I don't know if you mean the sidewalk alongside the street, or the sidewalk between the house and the street, but if it is from the house to the street, you might consider just using stepping stones. If you set them at ground level, you will not have a tripping hazard, although you will have to reset them every year or two as the soil in the yard gets higher from mowing and leaving the grass clippings on, etc. If it is the main walk alongside the street, you might be able to just patch it like someone else suggested. If it is the walk along the street, you should probably contact the city first as they may have new guidelines for sidewalks.

-- Green (ratdogs10@yahoo.com), February 26, 2000.

There is a method of mixing portland cement with earth and then wetting it a bit and rolling it to make a harder than plain dirt floor for sheds, etc. I have a friend that has experimented with it in his workshop, and it seems to work okay. It didn't work as well as he had read that it would, as it required more preparation than expected. I'm not sure of the details, but I know that the information is "out there" along with other interesting methods, such as the concrete made using shredded paper. If I can find the links or addresses I will post them. < http://www.northcoast.com/~tms/cheap.html> might be a place to start looking.

-- Jim (jiminwis@yahoo.com), February 29, 2000.

Thank you, everyone for your help. I'm still not sure what we will use. I appreciate your help.

-- Darlene (www.winterlove@theglobe.com), March 13, 2000.