Hi Mactec - Yes can get it in many flavours and additives. Will need to talk to a concrete chemist and find the one that gives best long term stability. I know epoxy gives very long term stability (been using it for 35 years) just don't know much about CSA yet. I have confirmed that the 80MPa CSA has an E=40GPa so that's impressive. Don't want it to severely micro crack some time into its life. Plus I shall have to figure how to couple it to the epoxy "skin" Probably after making the skin, wet out the inside then place some fluffy FG on the inside providing a key to the CSA. The thermal co-efficient of expansion is similar, FG to CSA both are about 10-12e-6/degC so that's good news as well. I have to build a benchtop for the sink for my new shed so shall make a terrazo top as a test from the CSA. Will learn a little from that.... I'm still looking for a good local short fibre CF supplier but I'm happy with the steel fibres I have....Peter
shrinkage - CSA does not shrink much compared to portland as the excess water added is completely used in the CSA chemical reaction. Portland has excess water to create a slurry and the excess water desorbs out over time. This shrinkage creates internal tensile stresses and as Portland has very low tensile strength it cracks over time. We know we want zero or very low internal stress in a machine part so this rules out Portland as a good material. But CSA seems to offer the best value in the cement area as it has small internal stress due to the complete utility of water in the reaction ie low volume change and you can get very low exotherm versions so the casting temperature stresses are minimised.
There are concretes based on portland and plaster of paris that look interesting too... slightly expanding and very stiff.....
https://www.timbermate.com.au/concremate/