Rejected concrete due to low Air-entrainment

[VBI]

If a concrete slab does not meet the required air-entrainment, can the slab be rejected entiriely? In this case, the testor failed to reject the concrete at the time of the pour even though he identified the issue at the time of the pour. He is now asking that the entire slab be removed and replaced a day later? Any thoughts? Thanks in advance...

 

[dik]

It may be a local condition, but, we normally leave rejection of the concrete to the Contractor; the testing agency is not normally the one that rejects the load.

Having said that, the testing agency should have advised the Contractor that the material was out of spec and that if not outright rejected and discarded that it may have to be removed; the testing agency should have to review this with the EOR and determine if the concrete was unsuitable unless he was given 'carte blanche' to have it discarded. Contractors often object to rejecting a load... for whatever reason.

Discarding depends on a couple of things (outside the contract)... if the material is unsuitable either from a strength or servicablilty requirement, it should go. It may depend on how far out of spec, but this should be a call by the EOR.

There's a lot less work getting rid of a load compared to removing hardened and finished concrete.

Dik

 

[Hoaokapohaku]

The question "can" the slab be rejected is strictly a contractural question. If the contract indicates a certain amount of air entrainment and gives authority to someone to direct that defective concrete be removed and replaced, and the concrete fails to meet the specifications, then the person with that authority "can" certainly reject the concrete. If the person indicated in the contract with acceptance/rejection authority is the "testor", then the testor can direct this. That would be unusual though, unless the testor is hired by the person with contractural authority and that person has delegated the authority to approve or reject the material to the testor. Normally it's either a design or agency engineer or architect, or perhaps a construction managament consulting engineer.

"Should" the slab be rejected is another matter that probably depends on the freeze/thaw conditions in the locale, and the general level of the contractor's cooperativeness in complying with contract requirements and providing quality work. If freeze/thaw is not an issue, the benefits of air entrainment are economy and ease of placement for the concrete supplier and contractor - not the durability of the concrete. If that is the case, there is really no reason to reject the slab.

 

[dik]

I've not been involved in any projects where the rejection of concrete has been stipulated... It's a bit problematic to do so. It's often included in the first site-construction meeting where the consultant's/owner's guidelines for samples, shopdrawings, test results are stipulated... It sometimes, however, becomes a problem during construction...

Most contracts usually only stipulate the minimum material properties... strength, slump, air, etc. and leave the rejection to others...

Dik

 

[Hoaokapohaku]

Dik...I guess this just shows how different different locales can be. I've never seen a public works project that didn't give someone authority to reject work or materials. Same with nearly all commercial projects. Only common exceptions are small residential or homeowner projects with the barest of bare bones contracts. Typically, the provisions won't be in the technical specifications. Rather, somewhere in the general contract provisions, usually under the title "Authority of the Engineer," or something like that. What good are specifications without provision for enforcement?

 

[dik]

I agree... but, it's like the elephant in the livingroom... it seems to be an issue that no one wants to set a hard and fast rule...

I've not done much public work related stuff... but I've not seen this on commercial projects.

Dik

 

[dik]

Sorry I should have added that in most contracts in these areas, either the engineer or the architect can reject work with a prescribed manner of doing so if it's not in conformance with the contract... and it's the only 'legal' manner in which funds can be withheld...

Dik