class I & II concrete 1

[boomerrr]

what is the definition of and/or difference between class I and class II concrete; also, what are their applications?

 

[RWF7437]

Do you mean class I and II "cement" ? See American Concrete Institute specifications.

good luck

 

[BigH]

Boomerrr - it always helps, as this is an international forum, to advise what country (or specifications) you are in (using) in order to get a more concise and quicker response. Different countries use different codings.

 

[genomty]

Big H is right, let me tell you a story, in my country for instance about 6 year ago used to be two type of concrete A and B, type A concrete allowed that 20 percent of your compressive streght results were below specified strength and conrete type B allowed that only 10 percent of breaks were below specification. Theorically, structural engineers should specified concrete Type A if they had used something that ACI named working stresses (ACI-318-1963 building code method) and type B if they had used the load factors and streght reduction (ACI-318-1983 or 1989 something like that building code).

It was a real pain in the #@% of CMT engineers because of drawings and specs usaully did not mentioned the review year of building code and specs just mentioned the standard, so contractors considered for bidding purposes the less expensive concrete which of course was the type A. I have always wonder if those guys managing the projects known the difference between the concretes and intentionally did not clarify specs to make projects cheaper or simply ingnore the standard and design methods. Of course no body used to put attention on conrete type until breaks are below specified strength, at that point, project managers start to look a guilty,structural said, come on, we all are engineers of course you should be familiarized with design methods, contractor said oh no! you did not even mention the review year or type of concrete in your drawings, owner, who usually did not know nothing about these issues, always was mad with everybody and trying to suit someone, Finally, CMT and structural guys usually recommended a structural review for those elements with low results and if reached strength was adequate the problem stop there, if not, oh God!, Ready Mix plant start to blame construction procedures, ask for a review on CMT lab procedures and methods.

Fortunelly, this standard was changed about 6 or 7 years ago and only concrete equivalent to the former named type B was left in standard.

 

[Chewi00]

Typically, in the US anyways:

Type I/IA are general purpose cements suitable for all uses where the special properties of other types are not required, where Type II cements contain no more than 8% tricalcium aluminate (C3A) for moderate sulfate resistance. Like advised above, check the ACI or ASTM codes for more in-depth explanation.

I find that most cements used now are Type I/II and meet the requirements for both.