Hello everyone
We had the foundations and the base slab poured. There was a large concrete pump truck and several trucks delivering concrete. From the delivery note, I saw that some of the concrete was discharged more than 90 minutes after being mixed at the plant. Water was also added in some cases, which was not noted on the delivery ticket.
Now the question: is it a problem that some of the concrete was somewhat "old" and that water was added in an unplanned way?
In a regulation I read, it said that ready-mixed concrete should be discharged from the mixer truck within 90 minutes.
I’m worried whether this is acceptable.
Thank you in advance
Regards
We had the foundations and the base slab poured. There was a large concrete pump truck and several trucks delivering concrete. From the delivery note, I saw that some of the concrete was discharged more than 90 minutes after being mixed at the plant. Water was also added in some cases, which was not noted on the delivery ticket.
Now the question: is it a problem that some of the concrete was somewhat "old" and that water was added in an unplanned way?
In a regulation I read, it said that ready-mixed concrete should be discharged from the mixer truck within 90 minutes.
I’m worried whether this is acceptable.
Thank you in advance
Regards
Hello,
When water is added, it changes the water/cement ratio. This ratio is responsible for the strength of the concrete. Could the added substance have been a retarder or a plasticizer? Both are concrete admixtures that do not have to be listed on the delivery note; only the concrete type and setting time are indicated there.
When water is added, it changes the water/cement ratio. This ratio is responsible for the strength of the concrete. Could the added substance have been a retarder or a plasticizer? Both are concrete admixtures that do not have to be listed on the delivery note; only the concrete type and setting time are indicated there.
RobsonMKK schrieb:
Layman’s question: should or must?I understand “should” in the sense of should = must.
BratacDD schrieb:
Could the additive have been a retarder or a plasticizer?No, it was water. This was also added by hand in writing.
Whether this affects the quality of the foundation slab cannot be answered with certainty. However, from a concrete technology perspective, it is fundamentally incorrect to add water to improve workability. The additional water in the cement paste leads to greater shrinkage and reduced strength. If you search for water/cement ratio and concrete strength online, you will likely find relevant charts. If you have concerns, you should consult your construction supervisor or an expert. Depending on the contract situation, this could be an independent specialist who can assess whether the shell construction company has done a poor job or not.
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