SHAPE SIMULATION OF GRANULAR PARTICLES IN CONCRETE AND APPLICATIONS IN DEM

Aggregate occupies at least three-quarters of the volume of concrete, so its impact on concrete's properties is large. The sieve curve traditionally defines the aggregate size range. Another essential property is grain shape. Both, size and shape influence workability and the mechanical and durability properties of concrete. On the other hand, the shape of cement particles plays also an important role in the hydration process due to surface dissolution in the hardening process. Additionally, grain dispersion, shape and size govern the pore percolation process that is of crucial importance for concrete durability Discrete element modeling (DEM) is commonly employed for simulation of concrete structure. To be able doing so, the assessed grain shape should be implemented. The approaches for aggregate and cement structure simulation by a concurrent algorithm-based DEM system are discussed in this paper. Both aggregate and cement were experimentally analyzed by X-ray tomography method recently. The results provide a real experimental database, e.g. surface area versus volume distribution, for simulation of particles in concrete technology. Optimum solutions are obtained by different simplified shapes proposed for aggregate and cement, respectively. In this way, reliable concepts for aggregate structure and fresh cement paste can be simulated by a DEM system.