Alkali Silica Reaction in Concrete with Granite - Laboratory Tests and Real Service Conditions

Damage to German concrete pavement by the alkali silica reaction has been repeatedly observed over the last two decades. Since certain slowly reacting aggregates are considered to be responsible for this damage they should be assessed in approved concrete performance tests before application in concrete pavement production. While the assessment of well-known alkali reactive aggregates in Germany provides reliable results, the assessment of granitic aggregates in concrete performance tests leads to unexpected indications of damaging ASR. In view of this, performance tests were carried out using top-layer pavement concrete compositions with granite in the coarse fractions and quartzitic sand. The results show that exposure to NaCl solutions unfavourably affects the alkali reactivity of the sand whereas the granite showed no indications of ASR. It is not known why this occurs in concrete with granite and quartzitic sand, but not with other slow reactive fine crystalline aggregates, e.g. greywacke. Investigations based on long time exposure of granite in the ASR mortar bar test reveal that the damage characteristics of ASR in granite particles differs clearly from that in fine crystalline slow reactive aggregates.     «

Damage to German concrete pavement by the alkali silica reaction has been repeatedly observed over the last two decades. Since certain slowly reacting aggregates are considered to be responsible for this damage they should be assessed in approved concrete performance tests before application in concrete pavement production. While the assessment of well-known alkali reactive aggregates in Germany provides reliable results, the assessment of granitic aggregates in concrete performance tests leads...     »