• Alistair Grinham

Project team:

  • Nathaniel Deering
  • Joe Cabonce

Project Brief:

testing procedure- applying patch

Current building codes assume no lateral export of chloride beyond the high tide mark in estuarine urban environments. This project aims to survey bridge surfaces for chloride presence as well as establish an aerosol chloride monitoring network. The project is in the early stages of development and will allow students to gain experience in development of new research methodologies and innovative environmental sampling techniques. This project will assist in developing knowledge and skills useful for CIVL2130.

Project Report:

Undergraduate students began the Bridge Chloride Icarus project with preliminary research and planning, outlining feasibility and setting key objectives. Two objectives were selected, to collect data on airborne chloride transportation rates along the Brisbane River in the CBD and surrounding suburbs. Secondly to provide students the opportunity to gain experience with experimental techniques and enable relevant research based learning.

Extensive research was conducted into best practice techniques for measuring/monitoring total chloride rates and concentration on structures. Due to the project focusing on bridges a limiting factor to testing was all tests must not cause any damage to the infrastructure, for these reasons a direct and indirect method were selected.

The first measurement technique was decided to be the Bresle patch test method (ISO8502-6/ISO8502-9), this test was decided due to it being a direct test to the concrete surface providing the total chlorides on the surface which can be extrapolated from prior research to estimate chloride gradient through the structure. The second measurement is the wet candle method (ASTM G140-2) which is a passive measurement of atmospheric chloride depositions, this was selected to identify if the distance from the Brisbane river mouth was proportional to chloride deposition and if so to what scale.

Challenges for the project were identified at an early stage, the primary challenge being access to the areas in which testing is required. Ideal testing locations would be the existing bridge network throughout Brisbane, students are in the process of overcoming these challenges to progress further. However currently Wet Candle Tests are deployed for initial feasibility and verification of testing technique, with the first sample providing a measure of 25mg Cl/m²/day directly adjacent to Moreton Bay.

The students have decided to continue this project forward into semester 2, with plans to establish the monitoring network and understand more about the chloride transport along the Brisbane River.

Non-destructive Bresle patch
Figure: Non-destructive Bresle patch
Wet candle test
Figure: Wet candle test