Degradation of bridges by internal expansive reactions? Portuguese case studies

Recently some concrete bridges in Portugal have shown premature deterioration due to intensive concrete cracking development mainly attributed to internal expansive reactions. An important experimental program was conducted in order to diagnose the causes and also prognostic the long-term behaviour of the deteriorated concrete bridges. The research conducted has indicated that the concrete cracking was mainly due to the occurrence of internal expansive reactions: alkali-silica reaction (ASR) and/ or delayed ettringite formation (DEF). The ASR was caused by the use of alkali reactive aggregates and the DEF by the high heat-curing temperature obtained during the setting and hardening in combination with the high portland cement content used in the concrete mix designs. Residual expansion tests were done in order to access the residual ASR and DEF reactivity. Most of the bridges show residual capacity to continue the expansion due to ASR or DEF, which has forced remedial measures against these expansive reactions, mainly associated with control of the ingress of water into concrete. To avoid these causes of damage the design and construction of new structures must follow the new Portuguese preventive methodologies.


  • English

Media Info

  • Pagination: 7p (oral presentations)
  • Serial:
    • Issue Number: 476

Subject/Index Terms

Filing Info

  • Accession Number: 01382624
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Aug 22 2012 1:24PM