Equilibria of the chemical composition of the concrete pore solution. Part I: Comparative study of synthetic and extracted solutions

Abstract

A critical review is made on Frattini and Hansen's results on the equilibria of the different ions present in the aqueous solution of cement paste after mixing. These values are compared with those obtained from results of squeezed cement paste specimens drawing the conclusions that the cement paste solution is oversaturated in $Ca(OH)_{2}$ just after mixing but the ions present in it are not in thermodynamic equilibrium because the solution is continuously evolving during early ages.

Also the increase in the solubility of the $Ca^{+2}$ ion because of the presence of $SO_{4}^{=}$ is discussed and attributed to the increase in the ionic strength of the solution.