2 X 2 inch grout cubes

[Belinda2761]

Why would the compressive strength of our grout cubes DECREASE from 7-day to 28-day?

 

[LittleWheels]

Is it a repeated strength drop or just for a single sample? I would first check for sampling or curing issues, possibly testing issues. Cubes were properly cured (always fully immersed)? Similar drying procedure/ moisture content when the cubes were tested?

 

[TigerGuy]

Sometimes they are damaged removing them from the molds. If the bond break (oil) is not applied properly, it can take real effort to get them free.

 

[Ron]

The mass of gang molds for 2x2 cubes is significantly greater than the mass of the cubes. Small disturbances of the molds result in large disturbances to the samples.