Prize for his poster at the Swiccomas general assembly

" Alkali-Silica Reaction in concrete leads to volume increase of ASR products. According to recent findings of Laboratory for Concrete & Construction Chemistry at EMPA, this volume increase can be as large as 66%. In the current study, I tried to answer the question if 66% of expansion of a single pocket of ASR product could lead to nucleation and growth of cracks. This was done by developing a semi-analytical model of expanding spheroidal inclusion embedded in an infinite medium and surrounded by a pre-existing ring-shaped crack. Stresses around the inclusion in a non-cracked configuration were obtained from the Eshelby's problem; Griffith's criteria was used to judge upon crack propagation. Semi-analytical results were confirmed with the numerical methods, namely combination of finite element method with cohesive zone model. Stress intensity at the crack tip showed strong dependence on the inclusion's shape, size and expansion value. However, neither a penny-shaped inclusion nor a sphere were the most critical shapes for the crack growth, but an oblate spheroid with the semi-axes ratio of 1/4 " Emil Gallyamov.