A new method for determination of segregation stability of pumped ready-mixed concrete: Rapid wet-sieved test

In the process of pumping, the segregation of concrete mixture will lead to the difficulty of construction, and even the possibility of pipe blocking. There is a lack of a quickly evaluation for on-site construction. In order to solve this problem, a rapid wet-sieved test was proposed in this study and then its feasibility was evaluated based on concrete mixes with different water-cement ratios. Subsequently, the influence of sand ratio on the segregation degree of concrete was investigated. The test results show that a combination of 2.36 mm screen size and 20 s vibrating time did the best. The wet-sieved mortar content and stratification degree were increased by 4.6%-25.2% and 0.3%-17.9% by pumping, respectively. With the sand ratio increasing from 0.40 to 0.60, the pumping pressure decreased by 51.9%. The linear fitting correlation between pumping pressure and wet-sieved mortar content (0.96) is better than that between pumping pressure and stratification degree (0.85), which indicates that the proposed test method can reliably characterize the degree of segregation during the pumping of ready-mixed concrete.