ASTM committee C01.25.01 sponsored a round-robin test to measure the PSD of cement. The participants were asked to use the PSD technique that they routinely use. The data requested from the participants included only the measurement method and the cumulative PSD. No detailed description of the procedure was required. Twenty-one organizations participated and the first four methods described in Section 2 were used. The identity of participant organizations remains confidential, therefore a letter is used to distinguish between participants.
Four portland cements provided by the Cement and Concrete Reference Laboratory (CCRL) to all participants were included in the tests: 131, 132, 135 and 136 (the numbers were assigned by CCRL). The characteristics of these cements, as measured in the CCRL proficiency program, are given in Appendix A. The standard cement, SRM 114p, was also used to establish a reference PSD for cement.
Appendix B summarizes in a tabular format all PSD data received from the participants of the round-robin. In the remainder of this section, the data is analyzed first to establish the reference distribution using SRM 114p and then to provide a detailed examination of the data with results for the four portland cements arranged according to measurement method. Unfortunately, in some cases (e.g., SEM, sieving), only a single set of results is available to represent each method. Therefore, it is not possible to analyze reproducibility between laboratories in those cases. Later in this report (Section 4), we provide a direct comparison of methods.