Ah, want a formula for dirt-crete do you. Sorry, this has to be done by test. The idea is to achieve the load capability specified and the amount varies greatly by area depending on the mix of sand, clay, rock and type of each in the dirt. Casts are made and tested and usually specifications call for quite a few tests. Some local companies can come close to guessing because they have experience with what is there. The previous answers are only half joking. It really does depend on where you are, but the mix will change as the soil conditions change.
It's difficult to give an intelligent answer, since we don't really know what the OP wants, what the soil composition is, wherever on the planet they may be (we aren't told that either) the traffic load, amount of rainfall/ freeze/thaw, etc, etc, etc, etc
You may also want too research some newer topping materials, that are applied and act as binders and solidifiers. Compaction its required, then a liquid is sprayed over the top, allowed to penetrate, and sometime resprayed, depending in loads . Being used for quick roads, sidewalks, parking lots for forestry vehicles, etc, where bringing in loads of aggregate is not practical, and a surface that does not break down with water is necessary. Grade, compact, and spray, is how it is explained.
Portland
Re: Portland
