Section 9.5.1 second speed in the mixer is set at (1260 rad/s [12000rpm]). It was found that using such as speed splashes the material in the mixer and thus reduces the efficacy of the mixer. In the original paper by Helmuth (footnote 4), who developed the prototype, the speed is set at (1047 rad/s [10000rpm]). All tests done in the papers referenced in the standards use (1047 rad/s [10000rpm]). Also, it should be consistent with section 9.6 that was successfully balloted (September 16, 2013) Thus, it seems that the speed in section 9.5.1 is incorrect and should be changed to use (1047 rad/s [10000rpm]). This ballot objective is to address that.
Keywordscement paste; high-shear mixing; hydraulic cement; rheology: Cement pastes; Hydraulic cement; Mixing; Rheology/rheological properties;
Ballot Item Approved as C1738/C1738M-2014 and Pending Publication