Adding mixing water in the field
Adding mixing water in the field
(OP)
I am wondering how to control the addition of water in the field. Contractors often want to add water to make a mix more workable, but doesn't this compromise the w/c ratio? Neither ACI 318 nor ACI 117 seem to indicate a tolerance for w/c ratio. Any comments?





RE: Adding mixing water in the field
RE: Adding mixing water in the field
this subject has been discussed under the "Admixtures" field so I suggest you look there for a good set of opinions and advice on this matter. Generally, the advice is DON'T DO IT.
Regards
Ginger
RE: Adding mixing water in the field
The difficulty is rejecting the Product during construction.
The QA ISO Standard has a)Acceptance, b)Acceptance with rework, c)Acceptance with concession, d)Rejection as the "power" you need. Prove it by video and recording "Indeterminate quantity of unauthorised water added" and use your own sample cylinder of concrete to reduce payment to contractor on c)Acceptance with concession of defective materials.
Contractors (usually poor quality anyway) who rely on "add water" usually rush Engineers with an artificial urgency. Defective material may need removal from the work! At the Contractor's expense. Have you ever heard about jackhammering out the 13th floor? A good contractor soon wins a reputation.
RE: Adding mixing water in the field
RE: Adding mixing water in the field
You can reject counterfeit reinforcement mesh or dirty reinforcement can't you! Oh you sign for a living!
RE: Adding mixing water in the field
RE: Adding mixing water in the field
Johnnie Browne aci II brownbagg@hotmail.com
RE: Adding mixing water in the field
a)all trucks have Certified calibrated water meters (ISO9000) and truck drivers were dismissed for adding water unauthorised. Otherwise reject the truck, before it discharges.
b)water may only be added after a tester or Engineer authorise it on the delivery docket and record it, signed.
c)Contractors supply their own plasticiser at their expense and obtain approval prior to pour, by submitting a Pour Procedure for approval with the tender document. This should state who authorises the addition of water and on what criteria, and makes a Contractor responsible. See how fast the practice disappears!!!!!!
d) Only use competent Conractors and Suppliers.
It is the Supplier and the Contractors' responsibility to verify that the finish product is as Specified, not the Client's or the testers or you, under ISO9000. You merely witness what happened, and by letting the practice occur, accept the defective material at who's liability?
Government jobs are not really different. Concrete does not know whether it is in a bridge or in the bony base of a column under 40 storeys. Best Practises Supplier and Contractor is a cost worth paying for.
Don't argue, have the power and the knowledge and the mechanism for acceptable practices only, in place always.
A good Contractor does not fight, he complies with the intent of the Specification and Best practices, for his reputation for quality at a fair price is tomorrows work!
Sorry if I upset you, but the original question has immense implications to the reputation of concrete as a preferred material in construction.