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Computers and Concrete
  Volume 15, Number 6, June 2015, pages 903-919
DOI: http://dx.doi.org/10.12989/cac.2015.15.6.903
 


Sensitivity and accuracy for rheological simulation of cement-based materials
Jae Hong Kim, Hye Rim Jang and Hong Jae Yim

 
Abstract
    The flow of freshly mixed cement-based material shows thixotropy, which implies some difficulties on robust measurement of its rheological properties: The flow curve of thixotropic materials depends on the used protocol. For examples, higher viscosity is obtained when the rate of shear strain is more quickly increased. Even though precise measurement and modelling of the concrete rheology needs to consider the thixotropic effect, engineers in the concrete field prefer considering as a non-thixotropic Herschel-Bulkley fluid, even more simply Bingham fluid. That is due to robustness of the measurement and application in casting process. In the aspect of simplification, this papers attempts to mimic the thixoropic flow by the non-thixotropic Herschel-Bulkley model. Disregarding the thixotropy of cement based materials allows us to adopt the rheological concept in the field. An optimized protocol to measure the Bingham parameters was finally found based on the accuracy and reproducibility test of cement paste samples, which minimizes the error of simulation stemming from the assumption of non-thixotropy.
 
Key Words
    cement paste; suspension; thixotropy; rheology; flow simulation; VOF techniques
 
Address
Jae Hong Kim and Hye Rim Jang : School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology,Ulsan 698-798, Republic of Korea
Hong Jae Yim : Department of Construction and Disaster Prevention Engineering, Kyungpook National University,2559 Gyeongsang-daero, Sangju, Gyeongsangbuk-do, 742-711, Republic of Korea
 

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