Maximum Saturation Values

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DavidHughes
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Maximum Saturation Values

Post by DavidHughes » Wed Sep 28, 2011 10:51 pm -1100

When a material is saturated with water is there a figure for what the Mass % is at saturation level or can this be derived from the porosity figures or other Wufi data?

Daniel
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Post by Daniel » Thu Sep 29, 2011 12:33 am -1100

You can derive the maximum saturation from the porosity - then you can convert it to % by mass...

Daniel
Dr.-Ing. Daniel Zirkelbach, Deputy Head of Department Hygrothermics, IBP Holzkirchen

Calina Ferraro
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Post by Calina Ferraro » Tue Oct 18, 2011 9:35 am -1100

Just to clarify what Daniel was saying, the porosity and maximum saturation are linked in the sense that maximum saturation occurs when all of the pores are filled.

Therefore, if you have a material with a porosity of 24% or 0.24 m3 of air/m3 of material, that means that the maximum amount of water that can fit inside of it is 0.24 m3 of water (filling up all the pore space). Since the density of water is 1000 kg/m3, this would correspond to a maximum saturated water content of 240 kg of water/m3 of material.

To get the mass percent (%-M), divide the water content by the density of the material. For example, if the material above has a bulk density of 1900 kg/m3, then when it is fully saturated, the water content by mass percent would be:

(240 kg of water/m3) / (1900 kg of dry material/m3) = 0.126 kg of water/kg of dry material OR 12.6 %-M

Note that although it is stated as a 'percentage', in lightweight materials, the %-M water content can be greater than 100% and in heavy weight materials (like the example above) it may never approach 100%.

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