An algorithm for computing the compressive strength of heterogeneous cohesive-frictional materials – Application to cement paste

An algorithm based on a finite element discretization of the lower bound yield theorem is applied to digital images, which allows the determination of the compressive strength of highly heterogeneous materials following a Drucker–Prager (or Mohr–Coulomb) yield criterion. The resulting optimization problem is usually very large and sparse and is solved using recent nonlinear optimizers based on the interior point method. The algorithm is validated for a laminated composite material, for which an analytical solution is available; and then applied to 2D slices of 3D digital microstructural models of cement paste. It is shown that the algorithm converges with mesh refinement towards experimental results.