A numerical model for description of mechanical behaviour of a Functionally Graded Autoclaved Aerated Concrete created on the basis of experimental results for homogenous Autoclaved Aerated Concretes with different porosities

The paper proposes a new concept for the Functionally Graded Autoclaved Concrete (FGAAC) and provides a numerical model to describe its mechanical behaviour. The model contains several material parameters describing damage growth and cracks propagation. They were assessed for the FGAAC by several laboratory tests like: 3-point bending, compact shear and modified Brazilian test done for homogeneous Autoclaved Aerated Concretes (AAC) with bulk densities in the range 400 divided by 700 kg/m(3). To achieve the goal efficient experimental procedures for the AACs testing were elaborated. The first step of this numerical model creation is description of the AAC gradual degradation and further cracks propagation in the above specified tests using XFEM approach. A good correlation with experiments was achieved. In second step the numerical model for theoretical FGAACs with using the material parameters describing damage growth in the MC was build. The mechanical behaviour of the FGAAC was analysed in virtual 3-point bending (3-PB) test. Comparison to the experimental 3-PB test for the homogeneous AACs leads to conclusion that the mechanical behaviour of the FGAAC is correctly modelled. Moreover, the proposed numerical model has potential application in civil engineering concerning designing of structural elements with build-in thermal protection. (C) 2019 Elsevier Ltd. All rights reserved.