Formation and expansion of ettringite crystals

Abstract The formation and expansion of ettringite crystals are discussed on the basis of principles of physico-chemistry. It is suggested that ettringite forms by a through-solution mechanism and that expansive force results from crystallization pressure as well as swelling pressure converted from the reduction of chemical potentials in the reaction of ettringite formation. Expansion depends mainly on the positions where ettringite crystals form. In a pore solution of high alkalinity, ettringite crystals form in situ and cause a large expansion. Alternately, they precipitate partially or completely in voids, thus giving rise to a little expansion or no expansion.

[1]  Arnon Bentur,et al.  Properties of type K expensive cement of pure components II. Proposed mechanism of ettringite formation and expansion in unrestrained paste of pure expansive component , 1974 .

[2]  P. K. Mehta.  Mechanism of expansion associated with ettringite formation , 1973 .

[3]  P. K. Mehta,et al.  Zeta potential and surface area measurements on ettringite , 1982 .

[4]  W. Hansen.  A discussion of the paper “scanning electron micrographic studies of ettringite formation,” by P.K. Mehta★☆ , 1976 .

[5]  P. K. Mehta.  Effect of Lime on Hydration of Pastes Containing Gypsum and Calcium Aluminates or Calcium Sulfoaluminate , 1973 .

[6]  V. Rossetti,et al.  Expansive properties of the mixture C4AS̄H12 - 2CS̄ I. An hypothesis on the expansion mechanism☆ , 1982 .

[7]  V. Rossetti,et al.  Expansive properties of the mixture C4ASH12 − 2CS III. Effects of temperature and restraint , 1983 .

[8]  Arnon Bentur,et al.  Properties of type K expansive cement of pure components I. Hydration of unrestrained paste of expansive component — Results , 1974 .

[9]  H. Taylor,et al.  Crystal Structure of Ettringite , 1968, Nature.

[10]  P. K. Mehta,et al.  Further Evidence for Expansion of Ettringite by Water Adsorption , 1978 .

[11]  P. K. Mehta.  Scanning electron micrographic studies of ettringite formation , 1976 .

[12]  D. Roy,et al.  C4A3S hydration, ettringite formation, and its expansion mechanism: II. Microstructural observation of expansion , 1982 .

[13]  P. K. Mehta.  Mechanism of sulfate attack on portland cement concrete — Another look , 1983 .

[14]  P. K. Mehta,et al.  Expansion of ettringite by water adsorption , 1982 .

[15]  E. Reardon,et al.  An ion interaction model for the determination of chemical equilibria in cement/water systems , 1990 .

[16]  Michael Gasser,et al.  Mechanism of Sulfate Expansion in Hydrated Portland Cement , 1988 .