Title: Effects of Viscosity on Pumping Concrete Behavior Using Computational Fluid Dynamics Method
Author(s): Wei Cui, Qiu-Wei Tang, and Hui-Fang Song
Publication: Materials Journal
Appears on pages(s): 117-126
Keywords: computational fluid dynamics (CFD); dense discrete phase model (DDPM); fresh concrete; pumpability; viscosity
This paper aims to find the effects of viscosity on concrete behavior in pipelines. Concrete was prepared according to ACI 304.2R-96. Experiments were conducted for measuring its workability by means of slump test. Fluidity and rheology measurements of fresh mortar were investigated. The concrete behavior in pipes was directly investigated using computational fluid dynamics (CFD) simulation, which is based on the Eulerian approach and the dense discrete phase model (DDPM). Concrete behavior including flow profiles, aggregate distributions, and migration was analyzed and discussed. It was observed that the flow characteristic varies from shear flow to plug flow with increased viscosity, and the aggregate distribution along the central axis is more homogeneous. Aggregate radial migration is more pronounced with increased shearing time, decreased viscosity, and enlarged size of aggregates. It was also found that concrete between 12 and 22 Pa·s (1.74 × 10–3 and 3.19 × 10–3 psi·s) is more suitable for pumping.