Evaluation of the Institution of Structural Engineers' procedure on concrete structures with alkali-silica reaction in the Netherlands

More than forty years ago in 1957, the first publication was published in The Netherlands indicating the possibility of damage due to ASR in a concrete structure. About ten years ago however the first concrete structure in the Netherlands with alkali-silica reaction (ASR) was documented. During the years before it was generally believed that this type of damage was not present in the Netherlands. In 1999, dozens of concrete structures have been proved to suffer from ASR. These structures have ages from 15 to 60 years. The types of structures vary from road bridges, water locks, bunkers, buildings etc. All structures have been made of portland cement concrete or concrete made of portland cement with a low content of blast furnace slag, the so called portland blast-furnace slag cement. For the evaluation of these structures the procedure of the Institution of Structural Engi-neers (ISE) has been adopted. The procedure will be modified to Dutch circumstances such as the concrete codes. Further some improvements are made in the draft of the new proce-dure as well as a partly more strict formulation. The modified procedure has been evaluated during a project on twenty different con-crete bridges in highway A 59 that were suspected of suffering from ASR. It was found that most of the structures have an extremely low uniaxial tensile strength. This observa-tion had a big impact on the maintenance strategy, more than is necessary according to the ISE procedure on basis of the other observations. This paper covers the different aspects of analysis of the affected structures, laboratory experimental research, structural aspects, and remedial measures taken to re-strengthen some of the bridges, rehabilitation, and monitoring of these structures.