A rigid particle discrete element model for the fracture analysis of plain and reinforced concrete
Concrete is regarded as a skeleton of aggregate particles of various sizes, almost
in direct contact with each other. The cement matrix acts as a filler and adhesive
enabling the structure to be able to carry tensile stresses.
A 2D circular rigid discrete element formulation based on the Discrete Element
Method has been adopted. Random assemblies of particles based on a given sieve
analysis can be generated enabling the simulation of the concrete structure at the
Contact models that are able to transmit moments through the contact plane
have been implemented, namely, a developed contact model adopting more than one
contact point at the contact plane. The steel reinforcement has been modelled with
1D beam finite elements or with 1D rigid discrete elements that interact with the
discrete rigid particles through contact interfaces. Softening has been introduced
into the microlevel constitutive equations.
The traditional DEM has been enhanced with a boundary wall driven by force algorithm,
an adaptive global damping algorithm and an arc-length control algorithm
increasing the range of applicability and the performance of the model.
The behavior of a double notched plain concrete specimen is investigated. Comparison
of results in terms of crack patterns and load displacement relationships up
to the peak load with both experimental and numerical results obtained using a
lattice beam element formulation showed good agreement.
The performance of the developed DEM model has also been evaluated for uniaxial
tension, uniaxial compression and tensile splitting tests. The developed model
showed good agreement in terms of peak strength, fracture localization and crack
Finally the interaction between the stiffness of the reinforcement normal to the
plane of cracking and the shear stiffness due to aggregate interlock is investigated.
Good comparisons in terms of shear force and shear displacement relationships for
a given crack width and reinforcement stiffness were obtained with known experimental