From the analysis of the methodology reported by the participants, it is clear that most of the participants used a laser diffraction method, either wet or dry. Although there is a wide range of methods used to prepare and analyze the specimen, some tendencies could be found for each method. This could be used for the basis of a draft standard method, at least for one based on laser diffraction.
In LAS-W, the following parameters could be established based on the results of this round-robin:
On the other hand, a better understanding of the influence of the following parameters on the results should be investigated further:
Since there were fewer parameters to select for the LAS-D method, the standardization should be less complicated. It is clear that the compressed air method is the most widely used, but this could not be a parameter to be fixed in the ASTM procedure because it depends on the manufacturer and not on the user. The pressure varies somewhat but the median value could be selected or more studies could be made to determine the influence of the pressure on the dispersion of the cement particles. The results are interpreted using the same methods as for LAS-W, i.e., Mie or Fraunhofer or both. As the size of the smallest particles could not be correctly determined using Fraunhofer, the authors suggest that both models be included. As it is not known how the participants selected the refractive index, further research to determine appropriate refractive indices should be conducted.
No clear conclusions could be drawn for the other methods due to the small number of participants using them.