THE APPRAISAL AND MAINTENANCE OF STRUCTURES WITH ALKALI-SILICA REACTION

Abstract

The damage to concrete structures from expansive and disruptive alkali- silica reaction (ASR), which first became apparent in the UK in the late 1970's, necessitated the development of new inspection, testing and appraisal procedures. These were brought together in a report in 1988 from the Institution (see IRRD 824463). This report has been substantially revised and updated in a 1992 report of the same title: Structural effects of alkali-silica reaction, technical guidance on the appraisal of existing This paper briefly outlines the background to the development of procedures in the report and their practical implications for the management of structures. The recommended approach facilitates the identification of the few structures with sensitive details and low strength reserves where severe ASR can result in major remedial measures. Structures with less severe ASR can be maintained in service for many years with careful monitoring, and, for some, localised protective measures. In many structures where ASR can be identified it is of too low a severity to influence performance significantly. Research needs and the necessity of specification to minimise risks of ASR in new construction are also highlighted (A).