2 posts
TimePosted 24/07/2008 16:04:42
Kelly71 says

Cement Ratings and Classifications


 I am a purchasing agent for an international customer and need to learn about the different grades and ratings of Ordinary Portland Cement. Specifically 42.5 M and 42.5 R. I currently have customers in the United States and Brazil. I believe 42.5 M is for the US and 42.5 R is acceptable in Brazil. Could someone enlighten me on the meanings of the M and R in the classification?

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Michael Clark
312 posts
TimePosted 25/07/2008 08:50:42

Re: Cement Ratings and Classifications

The cement strength class ratings under the EN197 cement standard are in fact 42.5N and 42.5R. The N and R suffixes mean “normal” and “rapid”. You must be very careful about being only guided by these aspects of the nomenclature. Cement will be classified as “CEM I”, “CEM II”, “CEM III”, etc. CEM I cements are composed of >90% cement clinker, gypsum and <5% supplementary materials. They correspond with cements classified under ASTM C150. CEM II, CEM III, CEM IV and CEM V cements are blended cements containing varying quantities and types of supplementary materials. They broadly correspond with ASTM Type IP or IS cements. If your customers are expecting Ordinary Portland Cement (those covered by ASTM C150 = CEM I cements) and you provide CEM II cements then you will be in trouble.