Cement-based material Bingham rheological parameter analysis method

Abstract

The invention provides a cement-based material Bingham rheological parameter analysis method. A nonlinear rotating speed-torque relation obtained by a coaxial double-cylinder rheometer in a partial shearing state is reasonably converted into a linear shearing stress-shearing strain rate relation, and Bingham rheological parameters of the cement-based material are obtained essentially. On one hand,when the rotating speed of the inner barrel is accelerated to a partial shearing state and disappears, relative slippage between the inner barrel and slurry or between the outer barrel and the slurryat a high rotating speed and testing errors caused by radial flowing of the slurry due to centrifugal force of the inner barrel are avoided, and side effects caused by increasing of the rotating speed of the inner barrel are effectively avoided; and on the other hand, a nonlinear rotating speed-torque curve is utilized to realize accurate solution of the Bingham rheological parameters of the cement-based material.

Description

technical field [0001] The invention belongs to the technical field of civil engineering, in particular to a method for analyzing the Bingham rheological parameters of cement-based materials. Background technique [0002] Cement-based materials used in civil engineering, such as plastering mortar and concrete of ordinary strength (compressive strength 30MPa to 60MPa), freshly mixed (paste prepared from a mixer and in a viscoplastic state) and subjected to external forces The flow characteristics under (such as spatula driving force or pump pipe delivery pressure) conform to the characteristics of Bingham fluid, that is, when the slurry starts to flow, it needs to overcome an initial stress, called yield stress, which shows a constant during the slurry flow process Viscosity is called plastic viscosity. The rheological characteristics of a typical Bingham fluid are as follows figure 1 As shown, in the shear stress-shear strain rate diagram, it is shown as a straight line wi...

AI Technical Summary

Problems solved by technology

[0011] Therefore, the existing method of using coaxial double-cylinder rheometer to test the Bingham rheological properties of cement-based materials has the following problems: 1) If the nonlinear influence caused by partial shear is ignored, the partial In the seemingly linear part of the speed-torque curve obtained under the shear state, the linear fitting to calculate the Bingham rheological parameter will underestimate the yield stress of the cement-based material and overestimate its plastic viscosity; 2) If the When the rotor accelerates to eliminate part of the shear state, the above-mentioned relative slippage between the inner cylinder-slurry or the outer cylinder-slurry, or the radial flow of the slurry caused by the centrifugal force of the inner cylinder will cause test errors and reduce the cement-based Accuracy of Material Bingham Rheological Parameter Analysis

[0012] To sum up, there is a dilemma in the prior art of using a coaxial double cylinder rheometer to analyze the Bingham rheological parameters of cement-based materials: the influence of the nonlinearity of the speed-torque curve at low speeds, and the influence of the slurry at high speeds. The impact of deviation from ideal flow state on test accuracy

Images