2018 Volume 72 Issue 1 Pages 33-39
The purpose of this research is to discuss that the effect of pretreatment drying of monocarbonate and coexisting substances on secondary ettringite formation. As a result, when monocarbonate simple substance was hydrated using an aqueous solution Na2SO4, ettringite was not generated. However, when monocarbonate and C-S-H was mixed and hydrated using an aqueous solution Na2SO4, the amount of ettringite was increased. And when monocarbonate and C-S-H with a low C/S ratio mixed, it was shown experimentally that amount of ettringite was greatly increased. And from the result of 27Al NMR measurement, the presence of tetracoordinate Al was confirmed only when monocarbonate and C-S-H mixed. Therefore, it was suggested that the change of the chemical form of Al from 6-coordinate of monocarbonate attribution to 4-coordination of C-A-S-H attributed to the formation of ettringite was affected.
