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Computers and Concrete
  Volume 2, Number 2, April 2005, pages 97-110
DOI: http://dx.doi.org/10.12989/cac.2005.2.2.097
 


Modelling the rheological behaviour of fresh concrete: An elasto-viscoplastic finite element approach
S. E. Chidiac and F. Habibbeigi

 
Abstract     [Full Text]
    Rheological behaviour of fresh concrete is an important factor in controlling concrete quality. It is recognized that the measurement of the slump is not a sufficient test method to adequately characterize the rheology of fresh concrete. To further understand the slump measurement and its relationship to the rheological properties, an elasto-viscoplastic, 2-D axisymmetric finite element (FE) model is developed. The FE model employs the Bingham material model to simulate the flow of a slump test. An experimental program is carried out using the Slump Rate Machine (SLRM_II) to evaluate the finite element simulation results. The simulated slump-versus-time curves are found to be in good agreement with the measured data. A sensitivity study is performed to evaluate the effects of yield stress, plastic viscosity and cone withdrawal rate on the measured flow curve using the FE model. The results demonstrate that the computed yield stress compares well with reported experimental data. The flow behaviour is shown to be influenced by the yield stress, plastic viscosity and the cone withdrawal rate. Further, it is found that the value of the apparent plastic viscosity is different from the true viscosity, with the difference depending on the cone withdrawal rate. It is also confirmed that the value of the final slump is most influenced by the yield stress.
 
Key Words
    concrete; FE modelling; rheological properties; slump test; Bingham model.
 
Address
Centre for Effective Design of Structures, Department of Civil Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
 

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