# soil cement project questions



## gobug (Dec 10, 2003)

I am in the process of beginning to build on my mountain property. The first step is to make the former garage (now workshop and breakroom) more comfortable to habitate in during my trips to work on construction.

My immediate goal is to finish the electrical to the workshop, get it inspected, and turned on. Before I can finish the electrical I want to complete the floor. 

Cement is way too expensive or time consuming. So I ordered a couple truckloads of crusher fine. Crusher fine is crushed granite, like road base, just finer.

I am nearly finished leveling the crusher fine in the workshop/breakroom. I want to make the crusher fine into a soil cement.

Now I am thinking is the time to add portland cement to the top and use a leaf rake to work it into the crusher fine. Then use my plate compactor (with an attached 5gal sprayer) to finish the first step.

The questions in my mind are:
how much portland and how deep?
how much water?
should I add a powdered pigment to the portland?

I have the portland. I must tote the water to the property.

I will appreciate any comments or ideas. Thanks ahead.
Gary


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## dirtman (Sep 15, 2011)

You would need very little water. I remember from a Ken Kerns book called the Owner built home or something like that that they used to use something they called no-fines concrete which was simply aggregate and portland with no sand. I assume it worked well though I'd probably be inclined to mix at least some sand into the mix to get a better finish. I've also heard of mixing asphalt emulsion into crushed stone and troweling it out. They called that Rub-R-Slate.


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## farminghandyman (Mar 4, 2005)

A normal concrete mix is about 5 rock and sand to 1 cement,

a yard is 27 cubit feet, and a footer mix is usually called 5 sack, and a floor mix is normally called 6 sack (the cement adds very little volume to the total as it worked in between spaces, of the rocks, and sand. when mixed


and mortar is a 3 to 1 ratio, normally, 

I would figure up the yards (cubit feet) of rock fines and figure about a fifth of it as cement, a sack of cement is said to be one cubit foot in volume, 

I have read where using a rototiller is good to mix it first before compacting, 

what I have found to mix your own cement unless it is very small project, that the savings is minimal in cost by the time one buys the rock and sand and the cement, 

that is my two cents,


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## gobug (Dec 10, 2003)

dirtman
I recall Ken Kern. I have his book, The Masonry Stove. Although I did not know he did a soil cement thing, that adds some confidence in proceeding.

I have played with asphault emulsion a bit. I don't think it will be a good choice inside a workspace.

Thanks for your reply.
Gary


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## gobug (Dec 10, 2003)

farminghandyman

You were correct on many things you wrote. Thanks.

I do recall someone using a tiller to mix the soil, cement, and water. My concern with using a rototiller is that it would be hard to control the depth. If I rototill to 4in deep, it is twice the portland and water as 2in deep. Plus it would be a all at once event rather than a few smaller trial runs.

Your comments got me to google soil cement. After a bit of reading I got the ratio of "soil" to cement as variable from 6:1 to 10:1. The cement can be as shallow as a few inches. Compacting is important. I will experiment with a couple coffee cans of the "soil", cement and water so I am prepared to do a larger area (like 100 sq ft) (then 250 then 500).

I will add a dry pigment to the cement prior to mixing. I will forget the leaf rake and use a 2" stiff tine rake to mix the cement.

Thanks again. Gary


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