Prediction of nonlinear pumping pressure loss of concrete induced by rheological property changes

Abstract

The pumping pressure loss of fresh concrete has traditionally been modeled as a linear function of the pumping distance. However, previous studies have suggested that this relationship is nonlinear in nature. This research has identified that the nonlinearity is due to changes in the rheological properties of fresh concrete during pumping. In this study, a new prediction equation has been proposed for the loss of pumping pressure for concrete mixtures with w/c ratios between 0.17 and 0.46, and an equivalent horizontal pipe length between 328 and 912 m. The equation provides a linear approximation of the nonlinear relationship of pumping pressure loss. To account for the effect of rheological changes during pumping, an empirical coefficient related to the initial slump flow of the concrete has been incorporated. The new function can improve the prediction accuracy of pressure loss by 25 % and 4.2 % for horizontal and vertical pumping, respectively.