A quantitative study of the influence of non-expansive sulfoaluminate cement on the corrosion of steel reinforcement

Abstract The corrosion resistance of steel reinforced mortar specimens made from non-expansive sulfoaluminate cement was investigated using Ordinary Portland Cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments, namely, continuous exposure in tap water, continuous exposure in 3.5% NaCl solution and intermittent exposure in 3.5% NaCl solution. The steel weight loss (WL) and the half cell potential (HCP) were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, sulfoaluminate cement provided adequate protection against corrosion. In continuous exposure in 3.5% NaCl solution, a higher corrosion was observed. In the case of intermittent exposure in 3.5% NaCl solution, the simultaneous action of free chlorides and oxygen, as well as the low pH of the pore solution, resulted in the depassivation of steel reinforcement and led to severe corrosion effect.

[1]  J P Broomfield.  ASSESSING CORROSION DAMAGE ON REINFORCED CONCRETE STRUCTURES , 1994 .

[2]  L. Santoro,et al.  Hydraulic behaviour of calcium sulfoaluminate-based cements derived from industrial process wastes , 1993 .

[3]  E. E. Larkin,et al.  Determination of C4A3S in type K cement and clinker using maleic acid-methanol and ammonium chloride-water as extracting agents , 1978 .

[4]  D. Roy,et al.  C4A3S̄ hydration, ettringite formation, and its expansion mechanism: III. Effect of CaO, NaOH and NaCl; conclusions , 1982 .

[5]  Josef Tritthart,et al.  Chloride binding in cement I. Investigations to determine the composition of porewater in hardened cement , 1989 .

[6]  C. L. Page,et al.  Pore solution composition and chloride binding capacity of silica-fume cement pastes , 1983 .

[7]  F. Glasser,et al.  MODIFICATION OF CEMENT PORE FLUID COMPOSITIONS BY POZZOLANIC ADDITIVES , 1988 .

[8]  G. E. Monfore.  Propiedades de los cementos expansivos, hechos con cemento portland, yeso y cemento aluminoso , 1966 .

[9]  C. Alexandridou,et al.  A study on the hydration products of a non-expansive sulfoaluminate cement , 1995 .

[10]  B. Georgali,et al.  Comparative investigation of corrosion resistance of steel reinforcement in alinite and Portland cement mortars , 1998 .

[11]  Deng Min,et al.  Formation and expansion of ettringite crystals , 1994 .

[12]  J. B. Newman,et al.  An assessment of four methods of determining the free chloride content of concrete , 1990 .