Investigation on Water Permeability of Concrete Based on Irregular Aggregate Packing Structure

In order to understand the influence of aggregate shape on water permeability of concrete,an irregular aggregate model is first constructed based on hyperellipsoid particles. Then,aggregate shape is quantitatively characterized (i. e.,elongation,flatness,roundness,sphericity) and the dynamic packing process of different aggregates is modelled by discrete element method,in which the interactions between particles are well considered. Afterwards,a three-phase mesoscopic model of concrete is established and the water transport in concrete is simulated by using a partial bounce-back lattice Boltzmann method. After validating the proposed model,the effects of aggregate content and shape on water permeability are studied. The results show that the permeability of concrete first decreases and then goes up at an increased aggregate volume fraction. Once the content of aggregate is larger than 50%,the formed connected transport path due to the overlapping of the interfacial transition areas (ITZ)results in the increase in water permeability. The changes in aggregate shape affect the flow path,the volume fraction of ITZ and thus the permeability. In contrast to flatness,the influence of elongation on water permeability seems to be more significant. As roundness gradually rises, sphericity initially increases and then goes down,while water permeability shows an inverse tendency. The minimum value of water permeability can be obtained when the roundness is equal to 1. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.