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In 1911 the cement laboratories of the Bureau National Bureau of Standards (NBS) began testing cement purchased for Government construction projects. The sampling required over 500,000 physical tests for fineness, specific gravity, tensile strength, and time of setting. These tests, however, did little more than determine whether the samples met current Government specifications, and in many cases the specifications were far from clear or consistent. Early in 1912, NBS called manufacturers and Federal engineers to the first Portland Cement Conference, in order to consider preparation of a single standard specification. As a result, a Presidential Executive order was issued on April 30, 1912, declaring that all Portland cement purchased by the Government was to conform to the specification agreed upon. Four year passed before final concurrence was reached and an acceptable specification was adopted.Gradually, improved test procedures and instruments disclosed the need for better understanding of the constitution and characteristics of cement materials, and testing became routine. [fromFrom: Measures for Progress by R.C. Cochrane, p. 125-6.]

 

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