Conductance of tricalcium silicate in water

Abstract

In this investigation of the earlier hydration of tricalcium silicate, the molar conductance was measured as a function of concentration at 25°C in the range of complete dissolution of tricalcium silicate in water (up to 0.3 g/L). Also the conductance of saturated and supersaturated solutions of tricalcium silicate at different water-solid ratio was carried out. The results sustained the electrical conductivity theories for dissolution. The ions in crystalline tricalcium silicate, Ca 2+, O 2−, and SiO 4 4− hydrolyze during dissolution process. The molar conductance of the completely dissolved tricalcium silicate in bi-distilled water is plotted as a function of the square root of molarity according to the Onsager's equation, a straight line is obtained indicating that tricalcium silicate is a strong electrolyte in water. The limiting molar conductivity λ o of tricalcium silicate solution was measured (1215 S. cm 2 mol −1 at 25°C). Based on the conductance data, a discussion on the dissolution and hydration mechanism of tricalcium silicate is given. The effect of sucrose (non-ionizable material) on the electrical conductivity of tricalcium silicate solution was studies. It was observed that the sucrose accelerates the hydration process in “through solution” reaction at the beginning of hydration, then the hydration is retarded at different times depending on sucrose-solid ratio, due to the adsorption of cationic and anionic species on the surface of tricalcium silicate.