Coarse granite aggregate in the accelerated tests stimulating interaction between alkali and silica

The research aimed at identifying characteristics of alkali-silica damage of concrete with coarse granite aggregate and establishing the extent to which different types of sand influence the reaction between alkali and silica in the concrete with granite aggregate. It was found that the exposure of concrete samples to the conditions of the accelerated tests can result in activation of alkali-silica interactions in coarse granite aggregate. The concentration of sodium chloride solution used as a medium in the tests of concrete at 60°C with external supply of alkali may affect the reactivity of two types of sand (quartz and river) used in the formulation of concrete blend with coarse granite aggregate. It is still unclear why this occurs in concrete containing granite and sand, whereas in concretes where sand is used in combination with other coarse aggregates, it is not activated. The results obtained so far do not permit unambiguous practical conclusions related to the reliable assessment of coarse aggregates and concrete formulations, as well as their safe use in WS-class concrete structures

Author: K. Fischer, L. Urbonas, D. Heinz

Section: Concrete

Keywords: concrete, alkali-silica reaction, granite coarse aggregate, river sand, quartz sand