I worked on a number of building sites during the early 60's at a time when many "terrazzo" floors were laid in public buildings and hospitals,and never saw one actually laid.The floor layers usually Italian,would not let anyone see the secrets of terrazzo floor laying,they would work in closed areas blocked off,or at night or weekends when there would be less workers about.You could see them doing preparation work ,but when it came to the actual floor laying they would not let anyone see the process.
The terrazzo floor was used to cover large areas of floor where a hard wearing surface without joints was required.They used marble chipping embedded in the concrete which when polished and sealed produced such a surface.
Colin