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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).

Expert opinion on the suitability of aggregates and concrete compositions

  • 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)

Testing with regard to alkali-silica reaction

Testing of aggregates

Service

Method

Accelerated mortar bar test at 80°C
(reference method)

Part 3 Alkali Guidelines

Accelerated mortar bar test at 70°C
(alternative method)

Part 3 Alkali Guidelines

Concrete test with fog chamber storage at 40 °C

Part 3 Alkali Guidelines

Concrete prism test at 60 °C

Part 3 Alkali Guidelines
RILEM AAR-4.1

Testing of concrete compositions
(ASR performance testing)

Service

Method

Concrete prism test at 60 °C
without external alkali supply

N F P 18-454

Concrete prism test at 60 °C
with external alkali supply

FIZ

Concrete prism test at 60 °C with two cored
specimens (with or without alkali supply)

FIZ

Concrete test with fog chamber storage
at 40 °C with cored specimens

FIZ

Analysis of damage resulting
from deleterious ASR

Fluorescence microscopy, polarizing
microscopy and SEM

VDZ-Service portfolio "Concrete and mortar"