on concrete mix report, how do i determine it's low permeability concrete

[AskTooMuch]

I've been reading how to make concrete less permeable but not sure when do you make the determination it's "low permeability" concrete.

I have concrete mix report, it has all the information like cement-water ratio, admixtures, etc.. I need to know whar to look to say this is low permeability or not.

 

[Settingsun]

Why do you need low permeability - waterproofing, chloride corrosion resistance, something else? And what is the situation/how critical to enforce low permeability?

Unless you've been given a permeability test result, the mix documents will only allow you to assess indirectly based on typical experience and trends. Concrete suppliers often have various test results for their standard mixes so it's worth asking. Otherwise the question is probably a bit too broad. Low permeability can be approached by mix proportions, admixtures, supplementary cementitious materials and probably other ways.

 

[RaptorEIT]

Asktomuch: The permeability of concrete to water depends mainly on the water-cement ratio (which determines the size, volume, and continuity of capillary voids) and maximum aggregate size (which influences the microcracks in the transition zone between the coarse aggregate and the cement paste). I would classify a concrete having a low w/c ratio and small aggregate size as "low permeability". However, these terms are all relative. I do not know of a definitive "cut off" point for classification as low permeability.

 

[Ron]

Reviewing the concrete mix design will not tell you the permeability of the concrete. As Raptor77R noted, the constituents will influence the permeability, with the water-cement ratio having the greater influence. In order to determine the permeability you'll have to test the hardened concrete. This is often done with trial batches set up prior to placement on the job.