Professor, University of Calgary, Calgary, Alberta
This paper reports on a statistical analysis of a large database of mortar-cube strengths from Canadian cement plants. The objective of the analysis was to provide summary data for decisions to be made concerning performance specifications for Canadian Standard CAN/CSA-A5 on portland cement. In particular, the suitability of the present limits on minimum strengths and the possibility of defining both lower and upper bounds for strength for various types of cements at various ages was examined.
Based on the statistical analysis, it is suggested that, at selected ages, establishment of lower and upper limits approximately three standard deviations from the mean strength are feasible and would probably be acceptable to all cement manufacturers in Canada. It appears that only two classifications for strength need to be established: one for Types 10, 20, and 50 cements (ASTM Types I, II, and V) and the other for Type 30 (ASTM Type III) cement.
Although a positive correlation is shown between surface area and some strength values, the scatter is so large that practical use of the correlation for the development of standards is unlikely.
Paper ID: CCA10599J