Discussion of Mix Proportions of Concrete for Long-Distance Pumping

Abstract

Long-distance pumping of concrete (up to 2000 m, with relay pumps installed at two locations) was carried out for placing invert concrete at a caisson—the construction site of a spillway discharge section. After quantifying the required performance and determining of the mix proportions of the invert concrete that would be used in the long-distance pumping, the authors focused on thixotropy as a factor that affects the pumping load. Through laboratory tests and using AE and a high-range water reducing agent with high dispersion effect, retention and pumpability enhancing admixture were found to be effective in reducing thixotropy.