Calibration and Validation of a 3D Discrete Element Model with a Moment Transfer Law for the Quasi-Static Behavior of Concrete

The Discrete Element Method (DEM) provides an efficient framework for simulating concrete under severe loading conditions involving cracking, discontinuities, and fragmentation. However, DEM formulations based on spherical rigid particles may produce an excessively brittle macroscopic response because particle rolling is insufficiently constrained, particularly under compression. To overcome this limitation, this study develops a three-dimensional DEM model for concrete incorporating a Moment Transfer Law (MTL) that introduces rolling resistance while preserving the computational efficiency of spherical particles. The proposed model combines cohesive and contact interactions with an elastoplastic rolling law formulated at the local scale. A calibration strategy is established to identify both elastic and nonlinear parameters from quasi-static uniaxial compression and tension tests. The model is applied to three concretes with experimental compressive strengths ranging from 33.8 to 67 MPa and splitting tensile strengths ranging from 3.0 to 4.7 MPa. The numerical simulations reproduce the compressive peak strength with relative errors below 1.2% and the available tensile strength values with relative errors below 0.7%. The introduction of the MTL significantly improves the compressive post-peak response by limiting excessive rolling between spherical particles and has a limited influence on the simulated tensile response while reproducing the available tensile strength values. The post-peak ductility is satisfactorily reproduced for the wet concrete, whereas it is overestimated for the concrete with higher compressive strength and the dry ordinary concrete. Because direct experimental uniaxial tensile stress–strain curves were not available, the tensile validation is restricted to splitting tensile strength. The simulated tensile post-peak response should therefore be regarded as a brittle modeling assumption rather than as a fully validated prediction. Overall, the proposed DEM–MTL formulation provides a robust and computationally efficient approach for reproducing the quasi-static compressive behavior and tensile strength level of concrete.