New Analysis Method for the Accurate Determination of Chloride Content in the Cement Phase of Concrete

摘要

Corrosion of reinforcing steel in concrete is on one hand a major security problem and on the other a cost driver, which is very often not appropriately considered. Corrosion induced by chloride leads to localized corrosion phenomena, which reduces the cross section rapidly. Already corroded steels have to be replaced. When the initiation of the corrosion can be predicted accurately, the reinforcing steels can be prevented from corrosion and a comparatively small rehabilitation measure is sufficient. The cost for rehabilitation, which is necessary approximately every 20 years, can be reduced to half the costs. For an approximate structure lifetime of 100 years this leads to enormous cost savings. Accurate measurements are the basis for understanding and defining the process of Cl-ingress into concrete structures. In this paper, the deficiencies of the standard methods are demonstrated and a new evaluation method is applied. The calibration process as well as real life applications on retaining walls are presented and discussed.