Effect of electrical field on TSA failure of cement-based materials

Abstract

The impact of electrical field on the sulfate attack of cement-based materials at low temperatures was studied to rapidly detect Thaumasite Sulfate Attack (TSA) in the laboratory and in future engineering. Sulfate attack of cement paste with 30wt% replacement of CaCO3 powder soaked in Na2SO4 solution, MgSO4 solution, or CaSO4 solution was measured under the condition of 5±2°C when an electrical field was applied. Appearance changes and compressive strength of the samples were tested to evaluate the corrosion degree. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopic measurements were applied to study the microstructure of the corrosion product. The test results indicate that sample damage was obvious, compression strength declined rapidly, and ettringite and/or thaumasite were found in the corrosion product after applying the electrical field for 90days. A muddy product with TSA characteristics was formed, and thaumasite composition was found in the corrosion product after applying the electrical field for 120days when MgSO4 solution was used as the corrosion medium. It is confirmed that an electrical field can accelerate TSA failure in cement-based materials.