Case 2 – Chloride Ion Attack
Navigation
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Maintenance and Diagnostics
Maintenance
- Cleaning of façade at least once a year can assist in the prevention of build up of chloride layer on the surface
- Regular inspection and monitoring the development of the cracks is necessary for façades of buildings at coastal and near coastal areas.
- Suitable instruments and techniques should be used to diagnose defects properly. Diagnosis involves a process in which experts investigate the buildings’ conditions, carry out tests, evaluate, make recommendations for remedial actions where necessary and predict the future performance of a building.
Diagnostics of Defect (see also NDT)
Inspection
To determine chloride content:
- break of pieces or drill small samples and collecting the dust produced
- treat samples with acid to dissolve the cement, and the chloride content is determined by titration against silver nitrate
- chloride ion meter and rapid field test methods to determine the level of chloride content
Common instruments for measuring chloride ion activities include:
(1) Chloride concentration (2) Half-cell potential (3) Corrosion rate
