[concretemasonry]

If you are grinding granite, you are trying to grind a very hard material.

How do you add "calcium"? Are you just adding milk or something with a different chemical composition. What kind of a mix and type of curing are you using?

Concrete is not for amateur kitchen chemists. Acryl 60 is not expensive if you consider you are working with it for something that is meant for a different purpose.

 

[concretemasonry]

If you have a source for expanded clay or shale, try to find an uncrushed natural fines aggregate (rounded) that is clean or could be washed more for casting. It is tough to find to find and is costly, but the amount needed is really pretty small and not a major cost factor, and the use can be learned.

I have found this at the plants from the old (epanded rotary kiln shale ot clay) Arkalite and Gravelite plants near West Baton Rouge, LA and West Memphis, AR (now probably Olcastle plants now) a number of years ago. Very good, but saturate it in water for a day or two before using because the absorption is very low and very sloooow. It is rounded, so it can pull out easily, but is great when bonded into the matrix before grinding.

 

[concretemasonry]

TS -

What manufacturer of the expanded shale is that?

Judging by the amount of aggregate showing, aas it a light dosing of LWT or only due to a shallow grinding depth? Sometimes the round aggregates take more grinding or polishing that the angular stuff that gets turned flat-side up during finishing.

It seems to be crushed because of the angular shape and not a natural gradation like Gravelite or the old Arkalite. I did see a few particles with the "halo". Is that from the old TXI plant or from Kansas?