Abstract: This paper presented results from an investigation program that concrete was eroded by sodium sulfate solution by means of Fourier transform infrared spectrum (FT-IR).The results showed that the primary deterioration products of concrete suffered from sodium sulfate attack are gypsum and ettringite.In interfacial transition zone ( ITZ),the quantity of gypsum decrease along thickness direction while the quantity of ettringite increase.In paste matrix,the quantity of gypsum is less and less while the quantity of ettringite is more and more from enterior to interior.The quantities of ettringite in ITZ are more than that in paste matrix.

Key words: sulfate attack;concrete;ITZ;FT-IR