It is not possible to predict the yield of the mix design because we don’t recommend a fixed quantity of bentonite. The quantity of bentonite used in the mix will depend on the pH and mineral content of the water used, the moisture content of the cement and bentonite, and the amount and type of byproduct within the locally sourced bentonite powder.
It is possible to calculate a gross estimate of the yield using 3.15 as the specific gravity of cement and 2.35 as the specific gravity of bentonite, but it must be considered a gross estimate as the expansion rate of the bentonite will not be the 10X volume change when it is mixed with fresh water. It will be a variable due to the redox reaction of the cement and water changing the properties of the water. This also increases the difficulty in calculating the yield ahead of time.
The best method of determining the yield is to mix a test batch using the actual materials that will be used on the project, although it should be noted that there will still be some differences between the test and the production grout, as the moisture content of the cement and bentonite will likely be different on test day versus on production day.