One-Dimensional Modelling of the Pressure Loss in Concrete Pumping and Experimental Verification

Abstract

An accurate formula with high precision for calculating the pressure loss in concrete pumping plays a significant guiding role in the design and service process of pump trucks. Based on the flow characteristics of concrete pumping, a one-dimensional model for the pressure loss was developed in which both the viscous force of the mortar in the lubrication layer and the blocking effect of coarse aggregate particles were considered. First, the complex geometrical shapes of the aggregate particles were reconstructed by using a HandySCAN noncontact 3D laser scanner and the inverse modelling software Geomagic Design X. Then, the equivalent spherical size of uneven aggregate particles was calculated according to the equal hydraulic radius principle. The blocking effect of the aggregate particles was converted into the wall roughness. Finally, an explicit expression for the pressure loss in concrete pumping was deduced by using Modi’s formula, Bernoulli’s equation and Darcy’s formula, and the calculated value was compared with the measured value at a corresponding experimental site. The results indicated that the pressure loss values calculated with the one-dimensional flow model, which are closer to the actual pumping pressure loss values, are more accurate than those obtained with a theoretical empirical formula.