Alkali-Silica Reaction in Transportation

In Alkali-Silica Reaction in Transportation, you'll learn ...

• How Alkali-Silica Reaction (ASR) causes premature deterioration in concrete pavement and bridge structures
• How to determine whether ASR is the main cause or a contributor to the deterioration observed is a concrete structure
• Critical decision factors when considering mitigation options for ASR
• Monitoring of structures after ASR mitigation/remediation

Overview

Credit: 6 PDH

Length: 132 pages

Alkali-aggregate reaction (AAR) is one of many factors that might be fully or partly responsible for the deterioration and premature loss in serviceability of concrete infrastructure. A subset of AAR is alkali-silica reaction (ASR), which involves various types of reactive silica (SiO2) minerals and alkali-carbonate. ASR relies on the formation of a secondary reaction product called alkali-silica gel that can generally be observed in concrete members affected by this reaction. ASR can result in expansion and cracking of concrete elements, leading to a reduction in the service life of concrete structures.

This course describes an approach for the diagnosis, prognosis, and mitigation of alkali-aggregate reactivity in transportation structures. A preliminary investigation program is implemented first to allow for the early detection of ASR, followed by an assessment (diagnosis) of ASR completed by a sampling program and petrographic examination of a limited number of cores collected from selected structural members.

In the case of structures showing evidence of ASR that justifies further investigations, this course also provides an integrated approach involving the quantification of the contribution of critical parameters with regards to ASR. Finally, you’ll learn mitigation options intended to treat the causes of ASR, as well as the symptoms of the deleterious reaction.