COLLOID ELECTROCHEMISTRY OF SATURATED CEMENT PASTE AND SOME PROPERTIES OF CEMENT-BASED MATERIALS

In a cement hydration product-electrolyte system the hydration product s are micron-sized charged particles. The principles of colloid electr ochemistry predict that in such a system each solid particle is surrou nded by a layer of concentrated solution of its counter-ion. The actua l concentration of this layer depends on the surface charge and the co ncentration of the solution away from the particle, i.e., bulk solutio n. Divalent counter-ions preferentially concentrate around the solid p articles. The principles also predict that the intrinsic diffusivity o f an ion is proportional to the square root of its concentration in a solution. The literature on the expressed pore solution, ionic diffusi vity through cement based materials, the formation factor, alkali-sili ca reaction, etc., has been examined from the point of view of colloid electrochemistry. Many of the reported but unexplained phenomena coul d be explained from the principles of colloid electrochemistry. (C) 19 98 Elsevier Science Ltd.