Concrete Workability Measurement in Non-Vertical Mixers
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Solution Overview
Problem
Existing methods for measuring workability parameters like slump, slump flow, threshold stress, and viscosity of concrete in mixers with non-vertical rotational axes are inadequate, especially for fluid concretes, as they rely on empirical formulas that require recalibration for each concrete formulation and cannot accurately measure parameters beyond slump.
Innovation Solution
A method involving varying the rotational speed of the mixer container to determine shear stress and speed gradient, using predetermined functions to extrapolate or approximate the relationship between these values, allowing for precise measurement of workability parameters without dependence on concrete fluidity or formulation changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indirect methods based on hydraulic pressure are used to measure slump, then measurement can be performed in the mixer container, but measurement precision deteriorates for fluid concretes and requires recalibration for each formulation
Solution Approach 1:
The patent replaces the hydraulic pressure-based indirect measurement method with a direct mechanical measurement system. A sensor directly measures the workability parameter (slump, flow rate, viscosity) within the mixer container, eliminating the need for hydraulic pressure conversions and empirical formulas. This direct measurement approach provides accurate results for fluid concretes without requiring formulation-specific recalibration.
Solution Approach 2:
The patent introduces a sensor as an intermediary device that directly interfaces with the concrete in the mixer container. This sensor acts as a mediator between the concrete's workability properties and the measurement system, enabling direct detection of parameters like slump, flow rate, and viscosity without relying on indirect hydraulic pressure measurements that require complex conversions and calibration.
2Measurement precision
If empirical formulas based on hydraulic pressure are used, then slump can be determined, but adaptability deteriorates when concrete formulation changes
Solution Approach 1:
The patent replaces empirical hydraulic pressure formulas with a direct sensor measurement system. The sensor directly measures the actual workability parameters of the concrete, eliminating the need for empirical formulas that are formulation-specific. This allows the system to adapt automatically to different concrete formulations without requiring recalibration or formula updates.
Solution Approach 2:
The sensor-based measurement system is self-adapting to different concrete formulations. Unlike empirical formulas that require manual recalibration when formulation changes, the sensor system automatically detects and measures the actual properties of the concrete regardless of its composition. The system serves itself by directly measuring the current state of the concrete without requiring external intervention or formula updates.
3Ease of manufacture
If hydraulic pressure measurement is used, then existing equipment can be utilized, but device complexity increases due to empirical formula requirements and recalibration needs
Solution Approach 1:
The patent simplifies the measurement system by replacing complex hydraulic pressure measurement and calculation systems with a direct sensor measurement approach. Instead of measuring hydraulic pressure, converting it to torque, applying empirical formulas, and recalibrating for each formulation, the system uses a sensor to directly measure the workability parameter. This reduces device complexity while maintaining or improving measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control and measurement of workability parameters in mixers with non-vertical axes, applicable to new concrete formulations without additional adaptation, and allows adjustment of parameters like slump and viscosity, improving handling and placement of fluid concretes.
Implementation Method 1
determining, for each of said at least two rotational speeds ω, a rotary drive torque C of the container, a value of shear stress τ of the concrete and a value of speed gradient γ̇ of the concrete according to the following relationships: τ=T(ω)·C ; γ̇=G(ω)·ω
Data Source
AI summary
A method for controlling at least one workability parameter of a concrete contained in the container of a mixer with a non vertical rotational axis, includes making the container turn at least at least two different rotational speeds; determining, for each of the rotational speeds, a rotary drive torque C of the container, a value of shear stress r of the concrete and a speed gradient γ of the concrete according to the following relationships: τ=T(ω)·C and γ=G(ω). ω where T and G are predetermined functions; determining a relationship of variation of shear stress τ according to the speed gradient γ by extrapolation and/or approximation from the determined values; and providing an indication of the workability parameter of the concrete based on the relationship variation.