Alkali-silica reaction - testing

In order to avoid damage resulting from alkali-silica reactions (ASR) the alkali sensitivity of aggregates or concrete compositions must be known so that if necessary appropriate measures can be taken. Tests on the alkali sensitivity of aggregates in accordance with the Alkali Guidelines stipulated by the German Committee for Reinforced Concrete (DAfStb) or according to RILEM can be carried out. In cases where the Alkali Guidelines stipulate the substitution of the aggregate or the use of cement with low effective alkali content 
(NA-cement acc. to DIN 1164-10) the alkali sensitivity of a concrete composition can also be proved by a performance test to ensure that aggregates or cements are not unnecessarily excluded from use.

In the case of concrete road coverings (e.g. on airfields or motorways) the ASR damage potential by alkalis from de-icing agents, which can intrude from outside into the concrete, is particularly high. It is therefore common practice to have the suitability of the concrete composition assessed by an expert by means of a performance test. The Research Institute is accredited as an expert for this by the Federal Highway Research Institute (BASt).

• Performance tests for the assessment of the ASR damage potential of concrete compositions in accordance with the general road circular No. 12/2006
• Basic and confirmatory WS testing for the assessment of the suitability of coarse aggregates (moisture class WS according to DIN 1045-2)