AbstractThe mesoscale structure generated in concrete plays a significant role in the mechanical properties and local failure behavior of mesoscale concrete. This work proposes a novel rigid-block discrete-element method (RB-DEM) for concrete modeling with random mesoscale structure. The results of the uniaxial compression using the RB-DEM demonstrated satisfactory agreement with experimental data. The RB-DEM does not only show satisfactory performance in simulation but also it is simple to use. The RB-DEM model can be built from any finite-element mesh generator, either open source codes or commercial software, which are readily available. The interfacial transition zone (ITZ) is modeled directly by assigning the weakened contact model or parameter at the interface between aggregate and mortar. The effects of ITZ parameters, aggregate volume fraction, and geometric shape on the stress–strain curve and crack propagation are discussed. This work provides a novel and efficient tool for the mesoscale fracture simulation of concretelike material considering the relatively large time-step of the DEM.Practical ApplicationsConcrete is one of the most common building materials, and its mechanical properties and crack evolution under pressure are extremely important for practical engineering construction. With the development of computer performance, scholars have used software or code to simulate experiments to improve efficiency and save costs (this is known as numerical simulation). This paper proposes a novel method named rigid-block DEM to simulate uniaxial compressive strength test of concrete, and the results were highly similar to the actual experimental results. This method can help researchers further study the influence of various concrete parameters on its performance. Compared with the traditional methods, the rigid-block DEM has abundant advantages such as simple model generation and high calculation efficiency, which provides a valuable reference for the future numerical simulation of concrete, and has certain guiding significance for engineering construction.