Impact of phosphate corrosion inhibitors on chloride binding and release in cement pastes

Abstract

The impact of three kinds of phosphate corrosion inhibitors (MFP, DHP and TSP) on chloride binding and release in cement pastes was investigated by means of chloride binding isotherms (CBIs), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Experiments of chloride binding, chloride release in deionized water and phosphate solutions were implemented separately. The regularity and factors of CBIs are well studied and the results of CBIs showed that phosphate inhibitors reduced chloride binding chemically due to reactions between Friedel’s salt and phosphates. Besides, the release of bound chloride can be well-calculated by CBIs. Furthermore, a modified CBI, taking effective phosphate concentration into account, has been established, and chloride penetration predictions have been made consequently.