2016 Volume 54 Issue 8 Pages 768-776
Long-distance pumping of concrete 2 076 meters (with relay pumps installed at two locations) was executed for the placement of invert concrete for the construction of a caisson for the Gotanda River Spillway Discharge Section ordered by Kawasaki City. Having quantified the required performance of concrete to be applied to long-distance pumping in the process of considering the mix proportions of the invert concrete, the authors focused on thixotropy as a factor that affects pumping load. Through laboratory tests and demonstration experiments, the use of AE and high-range water reducing agent with high dispersion effect retention and pumpability enhancing admixture were found to be effective for the reduction of thixotropy. Further, in actual construction, quality control was performed to suppress pipe blockages due to segregation and increased pumping load.
