Roller, Paul S.
Physical Chemist, Eastern Experiment Station, U. S. Bureau of Mines, College Park, Md
Roundy, P. V.
Cooperative Fellow, American Instrument Co., Silver Spring, Md
Pages: 16 Published: Jan 1941
Values for the surface area of portland cements were obtained by three different methods: the Wagner turbidimeter, air permeability, and a statistical calculation based on size-distribution data. In the Wagner turbidimeter (1), from the change with time in transmission of a beam of light through a suspension of the material, size distribution of the material and surface area are calculated. The turbidimeter analyses were made in the laboratories of J C. Pearson, Lehigh Portland Cement Co., who also kindly supplied the cements. Redetermination of these materials in the same laboratories about a year later gave surface area values that were consistently lower by about 5 per cent; we have taken for comparison the original values as being probably the more accurate.
Paper ID: STP43895S