Discrete Element Method Simulating Workability of Fresh Concrete

Modelling of workability test by means of a numerical approach based on concurrent algorithm-based Discrete Element Method combined with rheological model to simulate fresh concrete during its different processes may be a promising approach to form a bridge over gaps in understanding between respective aspects such as workability test results, rheological parameters and practical behaviour of fresh concrete, provided the knowledge will be established on how are workability and rheology affected by both raw materials and flowing conditions. In this paper the slump and slump flow tests, which are typical and commonly used workability tests, were first built up in a 2D system by the DEM. fresh concrete was represented by coarse aggregates with ellipse shape and the incorporation of effects of the (cementitious) matrix on the (due to gravitation or vibration) moving aggregate grains. Model parameters were correlated to the rheological properties. The slump and slump flow of fresh concrete was predicted. Moreover, experiments of slump test and rheometer test for different mixture were also carried out to verify the simulation. The results illustrate the DEM used in this study is quite promising. Currently, simulations of other workability tests are progressing. The influences of different factors such as particle size and shape, finer fillers and fiber will be discussed in coming papers.