Grout & Concrete Placement Times

[EngineeringEric]

I have a situation where a contractor placed cementious grout after the 90-minute bath to placement time. I, as the EOR, was not aware of this until a list was provided from 4 months prior. The 28-strength sample was taken after placement, and had 5460psi.

The final strength is more than I need or specified. What other problems should I be concerned about that may require additional investigation.
-Would inadequate consolidation be an issue?
-Uneven curing?
-Anything?

Thanks!

 

[EngineeringEric]

The title for concrete was because it made me curious for that as well and there is probably more information on that topic. (?)

 

[Ingenuity]

What is the application for the cementitious grout - block filling, baseplate bearing, wall panel ?

 

[EngineeringEric]

The grout was used to reinforce existing hollow CMU. The wall will be supporting decent point loads from columns above as well as some bearing walls for a two-story commercial space. So block filling in this application, but the question is more of a general for future considerations.

 

[Ron]

EE...keep in mind that the compressive strength testing done from samples taken in the field is to check the mix design, not the in-place concrete. The connection is by inference only, assuming reasonable placement, consolidation and curing methods were employed. If not, the lab strength and the field strength might not be close together.

The most common problem with cell fill is consolidation. Have the contractor check to see that the cells are properly filled using a variety of non-destructive methods....(infrared thermography, GPR, sounding, etc)

 

[wannabeSE]

Was the slump measured when the compressive strength samples were taken after grouting the wall? There is no time limit for transit mixed grout provided the slump requirements are met. See ACI 530.1-08 article 3.5A.

 

[dik]

As Ron indicated, it's my experience that the insitu strength (not field cured) can be twice the lab strength with infilled CMU's. Placing slump would be more critical.

Dik