Hongjing Dong, Xi Chen, Guangying Yang, Dandan He, Ying Dai and Pengfei He
The purpose of this paper is to obtain a constitutive model of cement-based material in the rheological stage, which owns the different water-cement ratio (w/c) and temperature…
Abstract
Purpose
The purpose of this paper is to obtain a constitutive model of cement-based material in the rheological stage, which owns the different water-cement ratio (w/c) and temperature and have a significant impact on the workability of concrete materials.
Design/methodology/approach
It is introduced a modified Arrhenius equation into the Herschel–Bulkley model, which is widely applied in rheological analysis and constructed an ordinary differential equation (ODE) of w/c from the Navier–Stokes equation. By solving the ODE, an approximate constitutive relation of cement-based materials included w/c and temperature is derived. Compared with the experimental results, the present model is validated.
Findings
The shear stress and shear rate curves with different w/c and temperature are simulated by the present method, and the present model can be applied to analyze the changes of apparent viscosity in cement-based material slurry as the w/c and temperature varying.
Originality/value
This work gives a mathematical model, which can effectively approximate the shear stress–shear rate relation with different w/c and temperature in the rheological stage of cement-based material.
Details
Keywords
Guangying Ma, Shurong Ning, Yunlong Hu and jun Gao
The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical…
Abstract
Purpose
The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical value in the actual hydraulic filtering system, the paper aims to find the relationship between the filtration ratio and the parameters of the hydraulic systems, such as the contamination level and the dirt-holding quantity of the filter.
Design/methodology/approach
The paper opted for the method of experimental analysis and simulation to determine the relationship between the filtration ratio and the parameters of the hydraulic system, and established a dynamic filtration ratio model.
Findings
The paper provides a preliminary model of dynamic filtration ratio, and the model shows that the filtration ratio is exponentially related to the contamination level and the dirt-holding quantity. Different filters have different influence coefficients. The filtering capacity for a certain particle size and the contamination level control of the filter for different hydraulic systems can be judged according to the dynamic balance equation of hydraulic systems.
Originality/value
The paper is useful in the selection of filters and in the precise control of the contamination level of the hydraulic system.