Bob, My experiance is only in laminated tops. Although, A company locally once manufactured homes with concrete by using a cement and sawdust mixture.(large not fine, such as when using a Dado blade dialed out to 1/2 to 3/4 inch.) By doing this they reduced the weight of the mixture and also made it possible to drill and even saw the material when cured. The finished product was durable and easy to work with. I do not know if this is of any assistance or not but there you have it.