Foundations and floor slabs were poured at our place

Hello everyone

Foundations and the base slab were poured at our site. There was a large pump truck and several trucks with concrete arrived. From the delivery note I could see that the concrete was sometimes discharged at our site well over 90 minutes after loading at the plant. Water was sometimes added, which was also not listed on the delivery note.

Now the question: is it a problem that sometimes "old" concrete was used and water was added unplanned?

In a regulation I read, it said that ready-mixed concrete in the mixing truck should be discharged within 90 minutes.

I am worried whether this is okay.

Thanks in advance
Best regards

Layman's question: should or must?

Hello,

When water is added, the water/cement ratio changes. This is responsible for the strength of the concrete. Could the additive have been a retarder or a plasticizer? Both are concrete additives that do not have to be listed on the delivery note, where only the concrete type and the loading time are indicated.

Layman's question: should or must?

I understand should in the sense of shall = must.

Could the additive also have been retarders or flowing agents.

No, it was water. It was also added by hand.

Whether this has an impact on the quality of the foundation slab cannot be answered with certainty. But purely from a concrete technology perspective, it is fundamentally wrong to add water to improve workability. The additional water in the cement paste leads to greater shrinkage and lower strengths. If you search on Google for the w/c ratio and concrete strength, you will surely find the relevant diagrams. If you have concerns, you should contact your site supervisor or expert. Depending on the contractual situation, you may also contact an independent specialist who can assess whether the shell construction company has done shoddy work or not.

I have now initially requested a statement from the company and will withhold the payment. Do I have to file a defect notice immediately or wait for the statement first?