STUDY ON THE FORMATION OF CARBONATE IONS IN CARBONATED PASTES

Abstract

In recent years, carbonated concrete has been attracting attention and many research are being conducted around the world. When analyzing carbonated concrete, samples are generally absolutely dried before analysis, and the liquid phase is not analyzed. Therefore, in this study, a dissolution test of carbonated paste was conducted and the liquid and solid phases were analyzed. In the carbonated region of the solid phase, calcite was dissolved as the liquid-solid ratio increased, and Calcite precipitated at pH＝12 and Vaterite precipitated at pH＝9. As a result of the liquid phase analysis, carbonate ions were dissolved from the solid and liquid phases, and a maximum of 24kg/m³ of CO₂ was dissolved. In addition, the dissolution of Ca^2＋ and CO₂ in the immersed water showed a positive correlation, and the dissolution rate of CO₂ increased as carbonation progressed.