Chemical analysis of deteriorated timber bridge elements

Maintenance of bridges is a very costly process and is ongoing for the life of the bridge. The current practice of bridge asset management of many types of council in Australia is based on the guidelines of Bridge Inspection Manual. This manual recommends the use of condition ratings for component parts of bridges, which are also used to prioritse maintenance. Incidently funding allocation by some councils are based on condition rating, although the manual does not recommend such practices. It is vital to understand the deterioration mechanisms of timber bridge elements consistent with the visual symptoms in ascertaining the present condition. This paper analyses the deterioration in timber bridge elements due to corrosive agents (acids). Samples were collected from lab examples and examined to study the changes in the molecular structure, moisture content etc., the FTIR technique has been used to analyse the surface morphology whilst the analysis of samples of 1mm thick were used to examine the internal changes. Results show that there is a strong degree of correlation between these parameters with visual symptoms