Bag Mixed Concrete Specification

[bigmig]

Besides just reading the read-i-mix bag, does anyone have some useful specs on field mixed (bagged) concrete they would be willing to share?

 

[thaidavid40]

What will this bag-mix concrete be used for? Bagged mixes vary so much between suppliers and by type that I'm not sure that one specification could cover them all properly. What concerns you most about specifying that the contractor simply follow the MPII?
Dave

Thaidavid

 

[CELinOttawa]

For small residential jobs (gazebos, porches, etc), I will frequently allow site batching of concrete and that then goes by the old proportions methods. Is that what you mean?

 

[dhengr]

Bigmig:
I’d say that the biggest issue is to warn against mixing it too wet. Many people will mix it too wet thinking this makes it easier to handle and work with, but this is at the detriment of strength and durability. Otherwise, the bag probably says 4000psi conc. or some such, with some generic descriptions of ingredients, and that’s about it. It’s meant to cover a wide range of uses, so there won’t be much very large aggregate in it.

 

[bigmig]

I mean buying a bag of read-i-mix concrete (like this:

http://www.lowes.com/pd/QUIKRETE-80-lb-Gray-High-Strength-Concrete-Mix/3006075)

and mixing it in a wheelbarrow and pouring some pads and footers
for a deck.

 

[SlideRuleEra]

Download the manufacturer's specification and instructions for the product. The spec for the product you have linked to is surprisingly complete:

Quikrete Concrete Mix, Product No. 1101

"Quikrete Concrete Mix, Product No. 1101, or Engineer approved equal, shall be mixed, placed, and cured in strict accordance with the manufacturer's instructions." Attach a printout of the manufacturer's info.

That's all it takes. I have not specified this particular product but have written many short, similar specs for using proprietary products. Note the chosen wording "Engineer approved equal". The only problem we ever had was Contractors deciding that if they "approved" of a certain similar product, that was ok. Not always the case.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net