|
Title |
Estimation of Yield Stress and Plastic Viscosity of Concrete Using the Slump Flow Test
|
|
Authors |
신태용(Tae Yong Shin) ; 한성호(Seong Ho Han) ; 김재홍(Jae Hong Kim) |
|
DOI |
https://doi.org/10.4334/JKCI.2020.32.2.165 |
|
Keywords |
슬럼프 플로; 레올로지; 빙햄모델; 항복응력; 소성점도 slump flow; rheology; Bingham model; yield stress; plastic viscosity |
|
Abstract |
The yield stress and plastic viscosity represent the rheological behavior of freshly-mixed concrete. Their measurements need a rheometer using a sample more than 20 L volume. A delicate control and analysis on the measurements, together with the high-volume sample requirement, makes it hard to apply the use of a rheometer in field. This paper proposes an analytical model to estimate the yield stress and plastic viscosity using the results of the slump flow test. The model is linearly approximated with its volume-of-fluid simulation results. A general tendency on the rheological properties is clearly confirmed with the proposed model: A high yield-stress concrete shows a higher slump flow, and the time to get 500 mm flow (T50) is dominantly proportional to its plastic viscosity. In addition, the model reflects a small but non-negligible effect of the plastic viscosity on the slump flow, also the effect of yield stress on T50, for the estimation. Finally, the model estimations are compared with the measurements using a commercialized rheometer such as ICAR and BML. Their biased measurements are discussed with the estimates using the proposed model.
|