Using "general use" cement, sand, liquid acrylic resin.
Supplies are available at a local home centre.
Ensure you have a large enough pail (Mixing Volume), or prepare for multiple batches.
Mix water/sand.
Mix in cement powder
Add the polymer.
Ensure mix is a batter, and doesn't run. Add sand/cement if required.
Apply the face coat. Then mix in fibres and pour the rest.
Keep concrete above 7 deg C for 3 days, strip form. Full strength at 28 days.