29 research outputs found
Stray current induced corrosion of steel fibre reinforced concrete
Stray current induced corrosion is a major technical challenge for modern electric railway systems. The leakage of stray current to surrounding reinforced concrete structures can lead to steel reinforcement corrosion and the subsequent disintegration of concrete. Steel fibre reinforced concrete has been increasingly used as the railway tunnel lining material but it is not clear if discrete steel fibres can still pick up and transfer stray current in the same way as conventional steel reinforcement and lead to similar corrosion reactions. The corrosion behaviour of steel fibres was investigated through voltammetry tests and electrochemical impedance spectroscopy. The presence of high concentration chloride ions was found to increase the pitting corrosion tendency of steel fibres in simulated concrete pore solutions and mortar specimens. The chloride threshold level for corrosion of steel fibres in concrete is approximately 4% NaCl (by mass of cement) which is significantly higher than that of conventional steel reinforcement
Calibration Method for the Determination of the FAME and HVO Contents in Fossil Diesel Blends Using NIR Spectroscopy
Ăśber konduktometrische und oszillometrische Bestimmungen von Alkaloiden mit Natriumtetraphenylborat
Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extractsÂą
This study proposes a method of direct and simultaneous determination of the amount of Ca2+ and Mg2+ present in soil extracts using a Calcium Ion-Selective Electrode and by Complexometric Titration (ISE-CT). The results were compared to those obtained by conventional analytical techniques of Complexometric Titration (CT) and Flame Atomic Absorption Spectrometry (FAAS). There were no significant differences in the determination of Ca2+ and Mg2+ in comparison with CT and FAAS, at a 95 % confidence level. Additionally, results of this method were more precise and accurate than of the Interlaboratorial Control (IC)