Abstract
Sp. Surface area of powder can be easily determined in any case by Blain's method, but this method has the following defects.
(1) Amendment must be made with a standard sample of a known sp. surface area.
(2) In measuring the sp. surface area of powder other than portland cement, silica cement and slag cement, the value of the porosity to be adopted is not clearly defined.
A new method of determining the sp. surface area not containing the above defects is proposed using Blains apparatus and the variation of the values of the sp. surface area was researched by changing the porosity. The result was that for powder consisting mainly of simple macro particles the value of the sp. surface area was, within the experimental error, always constant even if the porosity is changed considerably.
