Effect of time-dependence on the concrete transportation process

The fluidity of fresh concrete undergoes changes during transportation, exerting a direct influence on the pumping process and the ultimate quality of the hardened concrete. This study utilized the discrete element method to explore the impact of the time-dependence of fresh concrete on the transportation process. Specifically, a JKR contact model incorporating surface energy was employed to characterize the constitutive behavior of fresh concrete. The research established a relationship between surface energy and transportation time. The investigation delved into the mixing process after varying transportation durations through numerical simulations. The relative velocity between coarse aggregate and mortar increase with transportation time. The findings reveal a diminishing trend in both mixing and discharging homogeneity as transportation time increases. Enhancing the mixing speed of the drum to a critical value before discharge can ameliorate discharging homogeneity. However, excessive mixing speed may lead to detrimental effects on homogeneity.