Neutron radiation-induced volumetric expansion (RIVE) of concrete aggregate is recognized as a major degradation mechanism causing extensive damage to concrete constituents (Hilsdorf et al. 1978;Seeberger and Hilsdorf 1982;. Nearly 400 RIVE data obtained in test-reactors on varied rock-forming minerals were collected by Denisov et al. (2012). These data were input into the Oak Ridge National Laboratory (ORNL) irradiated minerals, aggregates and concrete (IMAC) database and were reanalyzed in order to develop a general empirical model for minerals RIVE and interpret the susceptibility of silicates toward expansion. The empirical models best regression coefficient (r 2 ≈ 0.95) is obtained by combining two different modeling techniques: (1) an interpolation-like model based on the relative distance to existing data points, and, (2) a nonlinear regression model assuming varied mathematical forms to describe RIVE as a function of the neutron fluence 3 and the average irradiation temperature. The susceptibility to develop irradiation-induced expansion greatly varies with the nature of minerals. Silicates, i.e., [SiO 4 ] 4-bearing minerals show a wide range of maximum RIVEs, from a few percents to what appears as a bounding value of 17.8% for quartz. The maximum RIVE of varied silicates appears to be governed, macroscopically, by three parameters: (1) Primarily, the dimensionality of silicate polymerization (DOSP), (2) the relative number of Si-O bond per unit cell, and, (3) the relative bonding energy (RBE) of the unit cell.

The radiation-induced volumetric expansion (RIVE) of aggregate-forming minerals causes damage in concrete exposed to high levels of fast neutrons fluence ($$>\,\sim \,10^{19}\, \hbox {n}\,\hbox {cm}^{-2}$$ > ∼ 10 19 n cm - 2 at kinetics energy above 0.1 MeV). Historical post-irradiation RIVE and Young’s modulus data obtained in test reactors were revisited using a polycrystalline homogenization model (self-consistent scheme) accounting for the aggregates’ minerals content and the formation of voids/cracks during irradiation. It was found that the formation of extra voids/cracks can contribute to the aggregate expansion more substantially than the cumulated expansions of aggregate-forming minerals. The rate of void creation appears to be inversely correlated to the silica content, although aggregates of higher silicate contents exhibit higher RIVEs. The loss of Young’s modulus decreases exponentially with the aggregates’ expansion. At a comparable RIVE level, the relative loss of modulus is more significant in aggregates of higher silica content.

The article ''Irradiation-induced damage in concreteforming aggregates: revisiting literature data through micromechanics'', written by Y. Le Pape,J. Sanahuja and M.H.F. Alsaid, was originally published electronically on the publisher's internet portal on 9 June 2020 without open access.