Portable Concrete Rheometer Using Linear Paddle Motion
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Solution Overview
Problem
Current methods for determining the rheological properties of concrete are inadequate for on-site use, as they require sophisticated setups, analytical skills, and often cause radial segregation of solid particles, failing to correlate with the subjective experience of workers.
Innovation Solution
A portable, hand-held trowel with a non-rotatably attached paddle and sensor means to measure the force acting on the paddle, allowing for easy, manual operation and data collection without causing particle segregation, and featuring an electronic module for evaluating and displaying the measured force data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standardized methods such as slump, slump flow or VEBE tests are used to characterize fresh state concrete properties, then the workability and initial fluidity can be described, but these methods are not able to characterize the rheological properties which have an important impact on production
Solution Approach 1:
The patent replaces complex rotational rheometers with a simple linear motion system. A paddle attached to a movable trolley moves linearly through concrete, with force measured by a load cell. This mechanical substitution simplifies the measurement system while capturing essential rheological properties (yield stress and plastic viscosity) that impact production, resolving the contradiction between measurement precision and ease of operation.
Solution Approach 2:
The device creates a simplified copy of the concrete manipulation process. Instead of using complex rotational rheometers that don't reflect actual construction operations, the patent uses linear paddle movement that mimics how concrete is actually handled in production (pumping, placing, finishing). This copying approach enables accurate rheological characterization that directly relates to production impact.
2Measurement precision
If a portable rheometer with pulley system is used to quantify torque needed to move an immersed paddle, then concrete properties can be determined, but the device requires elaborate setup and external power source making it mostly useful in laboratory
Solution Approach 1:
The patent extracts and eliminates the complex pulley system and external power source requirements from the rheometer. By using a simple linearly movable trolley that can be manually or automatically positioned, and a load cell for direct force measurement, the device achieves accurate concrete property determination without elaborate setup or external power, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The device is designed to be self-contained and self-sufficient. The trolley system can move autonomously or be manually operated without external power, and the load cell provides direct digital force measurement. This self-service design eliminates the need for complex pulley mechanisms and external power sources, making the device suitable for both laboratory and on-site use while maintaining measurement precision.
3Measurement precision
If rotating probes are used to measure concrete properties, then rheological data can be obtained, but the rotating probe causes radial segregation of solid particles falsifying measured properties
Solution Approach 1:
The patent inverts the measurement approach by using linear motion instead of rotational motion. Instead of rotating the probe through the concrete (which causes centrifugal forces and particle segregation), the paddle moves linearly through the concrete in a straight path. This inversion of the motion type eliminates the harmful radial segregation effect while still enabling accurate measurement of yield stress and plastic viscosity.
4Measurement precision
If yield stress is used as the primary parameter to describe concrete ability to fill formwork, then the most relevant parameter for self-filling can be identified, but this approach does not account for plastic viscosity which affects workability and stickiness
Solution Approach 1:
The patent segments the rheological characterization into two distinct parameters: yield stress (τ0) and plastic viscosity (μ). The measurement process captures both parameters separately through the linear paddle movement force data. Yield stress characterizes the concrete's ability to fill formwork under its own weight, while plastic viscosity characterizes workability, pumpability, and resistance to stickiness. This segmentation provides comprehensive adaptability for different construction scenarios.
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 accurate, on-site determination of concrete rheological properties, correlating with the subjective experience of workers and providing reliable measurements without the need for complex setups or training, improving the ease of handling and finishing concrete.
Implementation Method 1
sensor means for determining a force acting on said paddle
Data Source
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AI summary
The present invention concerns a portable hand-held device (10) for determining rheological properties of concrete comprising a handle (11) for manually operating the device, a paddle (12) non-rotatably attached to said handle (11), sensor means (14) for determining a force acting on said paddle (12), an electronic module (17) for evaluating data collected by said sensor means (14), and an electrical power source for supplying electrical energy to said sensor means and said electronic module. The invention also concerns a method for determining rheological properties of concrete using such a portable, hand-held device comprising the steps of completely immersing said paddle (12) of said device into concrete;manually moving said paddle (12) along a linear path through the concrete for a predetermined distance;measuring a force acting on said paddle (12) during its movement through the concrete and collecting said force data; evaluating said measured force data and displaying the evaluated results.