Numerical Prediction on the Effects of the Coarse Aggregate Size to the Pipe Flow of Pumped Concrete

摘要

The objective of this study is to numerically investigate the effects of coarse aggregate size on the pumpability of concrete. In actual construction of super-structures, the coarse aggregate size plays a determining factor on concrete pumping. Thus, depending on the coarse aggregate sizes, the properties of lubrication layer which is the major role facilitating concrete pumping, were numerically simulated using shear-induced particle migration analysis. Moreover, the particle shape effects according to the coarse aggregate sizes were also considered in numerical simulation to precisely simulate the actual flow conditions. For verification, 1,000m long full-scale tests with three different coarse aggregate sizes (10, 20 and 25mm) were conducted and compared with numerical results. It could be found that when concrete is being pumped, the rheological properties of concrete and lubrication layer highly depend on the coarse aggregate size, which consequently influences the flow condition of pumped concrete, whereas the thickness of lubrication layer remained almost constant irrespective of the coarse aggregate sizes.