5.1 This method is intended to help manufacturers determine the relative pack-set tendency of their cement(s). The test establishes a pack-set index which, when properly correlated with field performance, is useful in predicting or preventing field unloading difficulties.

5.2 The test is an aid to routine control during cement production and is not suitable for specification purposes.

5.3 In general, field performance of cement flowability is satisfactory when the pack-set index as determined on freshly ground cement averages 0 to 15 and is unsatisfactory when the index exceeds 25. Any prediction of field performance of cement flowability measuring 16 to 25 is tenable. These are general ranges and the field performance of individual cements may not necessarily fall within these ranges. Additional conditions, after the cement has left the control of the manufacturing facility, can affect the apparent pack set index as well.

5.4 Any attempt to apply the critical range of pack-set index numbers based on freshly ground cement to job cement without special treatment of the sample would be problematic. The test is a "GO-NO GO" type of test and should not be used for specification purposes.

5.5 The pack-set index of field cement can be evaluated in terms of the pack-set index ranges of that cement as determined when freshly-ground. This comparison can aid the manufacturer in producing cement that offers the best field performance for pack-set properties.

5.6 Silo storage of cement may result in a greater amount of consolidation than this method is designed to induce, and the resulting forces required to overcome that consolidation are not measured by this test method.

5.7 Pack set is not to be confused with "warehouse set" which results from surface hydration of the cement from adsorbed moisture.