I need some advice as to what you would recommend as testing regieme for a slipformed concrete chimney stack. Specifically number of concrete cube tests per shift, or any other recomended tests. Is there any codes that give reference to this.
Depending on where in the world you are working, your local codes of practice should give guidelines.
Also consider what issues could affect concrete quality :
1) Change of worker shift as you mention
2) Different mixing plants or readymix suppliers if more than one
3) Difference in day/night working conditions and temperature
4) Cement from different silos/batches and aggregate stockpiles with different moisture contents etc
For every change that may give rise to a change in mix quality, you will neeed a batch of cubes. The batch should consist of probably 3 cubes for the statistical and contractual testing, plus at least 3 cubes to be tested at various early ages to pick up any major problems in time.
It may also depend on the cross-section of the structure, but I suggest at least one batch of cubes per 50 cubic metres of concrete.