Case 1 – Alkali-Silica Reaction
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Maintenance and Diagnostics
Maintenance
Progress of ASR can be slowed down if it is detected at a relatively early stage. This suggests that regular inspection on the performance of façade and immediate repair should be done to remedy such defects.
Whenever a problem has been identified, a programme of monitoring the future behavior of the structure will ensure that it remains safe, until it eventually needs to be replaced.
Diagnostics of Defect (see also NDT)
Identification: ASR-induced cracks often have a distinct pattern, including map-like cracking (resembling a map with irregular polygonal shapes) or parallel cracks. These cracks typically occur in areas exposed to moisture, such as near joints or on surfaces subjected to water.
The best technique for the identification of ASR is the examination of concrete in thin section, using a petrographic microscope.
Alternatively, polished sections of concrete can be examined by scanning electron microscopy (SEM).
Chemical tests have also been shown to be effective.
