2018 Volume 72 Issue 1 Pages 136-143
Assuming that concrete flowing in a pipe forms a two-layer flow which consists of the concrete and a thin film of water present in the gap between the concrete and the pipe wall, the flow rate can be obtained from the Bingham flow rate, the amount of slip displacement of the concrete and the volume of the water film. In this study, flow rate measurement was carried out at three different levels of head differential at the inlet of the funnel pipe, using the O type funnel test equipment fitted with a sample container at the top. In addition, pressurization dewatering test was used to calculate the thickness of the water film occurring at the pipe wall surface and the slipping velocity of concrete from the amount of dehydration. The Bingham flow rates thus determined were put in the Buckingham formula for estimating rough values of rheological constant. The flow rate predicted by multiplying this approximate value by the correction coefficient and the actually measured flow rate by the pumping test apparatus are relatively close to each other, indicating the possibility of predicting the flow rate easily.
