Gel as New Anticorrosion Medium in the Post Tension Industry – Scientific Study

Abstract

Hydrogen damage and embrittlement is a well-known danger in the post-tensioning industry as failures of systems has been documented due to spontaneous cracks of the steel constructs induced by corrosion. The solution to this problem is the use of anti corrosion material.

Over the past years an anti corrosion gel has been introduced to the market and has been successfully used in unbonded external post-tensioning systems ever since.

The innovative production process and chemical composition, where a highly resilient polymer is dissolved completely and irreversible in base-oil, are the reasons for the gel’s long time stability and advantageous characteristics. Those are the thixotropic behaviour, which ensures an easier and safer application, as well as the fact that there is no decomposition of the components and therefore the gel exhibits zero oil separation.

Additional to experiences in applications like mono-strand- and anchor-filling, which confirm the durability of the gel, a study was developed in cooperation with the Technical University of Vienna to verify the long-lastingness from a scientific point of view.

The method used for this study is based on comparing the raw material of the gel with freshly produced gel as well as material which has been scientifically aged (through applying of heat, oxygen, pressure and exposure to water) and which has been used in a post-tensioning application for years.

The results confirm the long time stability of the anticorrosion gel as well as deliver a base for a prediction model which shows a possible alteration of the gel’s composition and durability when it’s used for 50 years and longer from a chemical point of view.