Long term testing of polyester yam and product at 50°C and 23°C in different environments

The kinetics of the hydrolysis of polyester yams used in geosynthetics is progressively better understood, thanks to temperature accelerated testing. The paper recalls the different phases of the research program launched in 1990 by Terre Armée Internationale. After the findings of the previous steps performed at elevated temperatures (95°C and 80°C), the paper presents the initial results of the third and long-term phase, at 50°C and 23°C. Now, after only two years, only the tests conducted in an extremely aggressive media can be usefully investigated. They suggest that two different Arrhenius coefficients might have to be considered in the kinetics of hydrolysis above and below the glass transition temperature. This results in practical consequences for current designs, identified at the end of the paper.