Study On Deterioration Mechanism Of Concrete And Development Of Mending Materials In The Metallurgy Environment

This paper was aimed at the deterioration machanism of concrete in the metallurgy environment such as the slag powder dehydration system of the first blast furnace and the continuously-casting roller foundation of the frist steel-making plant of Shanghai Baosteel Company. Based on the engineering investigation and corrosion parameter tests, deterioration mechanism of concrete in these two typical metallurgy environments was studied by a lot of microstructure analysis method. The mending materials were developed by simulation tests and used in the actual engineerings. Finally the models of life prediction of concrete at the corrosion form of corrosive medium and high heat were established and proved.By the component test of corrosive medium, mechanism performance and the carbonization degree of concrete and a lot of microstructure analysis such as X-Ray Diffraction Analysis(XRD), Scanning Electron Microscope (SEM), Infrared Spectrum Analysis(IR) and Hole structure analysis of concrete(HSA) were done to analysis the difference of performance, component and microstructure of concrete before and after corrosion. Because of the penetration of chloride and sulphate and the carbonization of concrete, the crystal such as gypsum, hydrated calcium chlorine aluminate, calcium carbonate and single-carbon calcium aluminate were formed and grown up. This was the main reason of the deterioration of concrete in the corrosion form of corrosive medium. Compared with other reasons, the chloride was the foremost reason because of the biggest penetration depth and rustiness of steel.The distribution of temperature stress was calculated by finite element analysis. The results showed when the surface temperature of concrete was higher than 110℃, the temperature stress was more than 4 MPa without regard to the creep. This might be lead to the damage of the surface of concrete. At the same time, a lot of microstructure analysiss such as XRD, SEM, IR, HSA etc. were done to analysis the difference of the component and microstructre of concrete before and after corrosion.