Bonding Performance of Mineral Admixture to Chloride in Sea Water

The bonding performance to chloride of plain paste,pastes with 0~50% fly ash,paste with 0~65% GGBS (ground granulate blast furnace slag) and paste with 0~8% silica fume was investigated in NaCl solution and sea water.The results show that the bound amount of chloride was about 4.8~4.9 mg Cl-/g paste in NaCl solution,and it was reduced by about 33%~46% in sea water because the formation of ettringite resulted in the decrease of Friedel's salt content.GGBS or 0~35% fly ash could improve the bonding capacity of the pastes to chloride,while silica fume decreased it.The bound chloride content was maximal for pastes with 35% GGBS or 15% fly ash.Additionally,the bound chloride content of the paste with a great deal of GGBS increased with the increase of immersion time.The mechanism was also investigated by DTG (differential thermomechanic analysis) and XRD(X-ray diffraction)techniques.