  Volume increase between the reactants and the products of alkali silica
reaction could reach up to 100%. Taking place inside the aggregates, ASR
imposes internal pressure on the surrounding material. In the current paper, we
study the possibility of crack growth due to such internal loading. This study
is done by employing a semi-analytical mechanical model comprising an elastic
solution to a well-known Eshelby problem and a linear elastic fracture
mechanics solution to a ring-shaped crack encircling a spheroidal inclusion.
The proposed method implies the availability of pre-existing micro-fissures
within the aggregate.
  The study reveals dependence of the crack growing potential on the spheroid's
shape: the larger is the ASR pocket - the longer crack it can open. Two most
critical shapes, causing a highest stress intensity factor and developing the
longest crack, are a sphere and a spheroid with 1/4 aspect ratio respectively.
The size analysis of the problem suggests a critical spheroid's radius below
which no crack growth is expected. For a chosen material properties and
expansion value, such radius lays in the range between 0.1 and 1 micrometer.
Independently of the expansion value and the shape of the pocket of ASR
product, the maximum crack length has a power-law dependence on the size of a
spheroid.
  All the theoretical predictions are confirmed by a numerical model based on
the combination of the finite element method and cohesive element approach.
