Does the vibrating rod used to vibrate the test block affect the strength of the test block, and what causes the aggregate separation? There may also be other factors.

This is standardized, but I forgot the details. It seems that the slump below 10cm is better with a vibrating table and above with a tamping rod. When the slump is large, the vibrating table is easy to separate, and the upper layer becomes slurry and the lower layer is gravel. Actually, the actual operation is too dry. If you can't poke with a tamping rod, you can't. There are many reasons for aggregate separation, generally large slump; Or too little cement slurry can not wrap the aggregate. Mostly these two situations.