INFLUENCE OF KCL ON THE HYDRATION OF ALIT E

This paper discusses the influence of KCl on the hydration of alite, t hat is a main component of ordinary Portland cement. The amount of KCl addition was changed from 0 to 10% (counted by Cl). Heat liberation o f the early hydration of alite with or without KCl were measured by co nduction calorimeter. The rate of heat liberation of alite was acceler ated by the addition of KCl, When the amount of KCl addition (counted by Cl) was 2 %, the hydration of alite was accelerated most. The induc tion period of hydration was reduced by the addition of KCl. But, the induction period of hydration of alite with KCl did not disappear like in the case of alinite hydration. The reaction ratio of alite was mea sured by XRD at late stage of the hydration. The reaction ratios of al ite with 2 % KCl (counted by Cl) showed the maximum values, until the reaction time 7 day compared with the case of other dosages of KCl. Ho wever, the reaction ratio of alite without KCl was showed the maximum value of 83% after 28 day. And the larger the amounts of KCl addition, the smaller the reaction ratios of alite. The CaO/SiO2 ratio of calci um silicate hydrates produced by the hydration of alite with 2 % KCl ( counted by Cl) was showed the maximum value until the reaction time 7 day. At the reaction time 28 day, the ratio of CaO/SiO2 of hydration p roducts became large value with the amounts of KCl addition. Calcium s ilicate hydrates for the hydration of alite with KCl was contained chl orine. The larger the amounts of KCl addition, the bigger the Cl/SiO2 ratio of hydrated products, When the dosage of KCl was 10% (counted by Cl), the ratio of Cl/SiO2 of hydrated products was 0.29.