Fly Ash Adsorption Measurement via Fluorescence
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Solution Overview
Problem
The presence of activated or unburned carbon in fly ash interferes with the air-entraining agents' ability to entrain air in concrete, leading to suboptimal air void content and increased susceptibility to frost damage, necessitating a method to accurately determine and mitigate the adsorption capacity of carbon in fly ash.
Innovation Solution
A method involving the use of optically active reagents to measure the adsorption capacity of fly ash through fluorescence emission intensity, allowing for continuous monitoring and automated dosage of a sacrificial agent to passivate the carbon, combined with an improved ash handling and reagent injection system for uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual foam index test or methylene blue adsorption is used to determine fly ash adsorption capacity, then the adsorption capacity can be determined, but the measurement is subjective and cannot be automated
Solution Approach 1:
The patent replaces manual mechanical testing procedures (foam index test, manual adsorption measurements) with an optical measurement system that uses fluorescence emission intensity to determine adsorption capacity. This substitution enables automated measurement while maintaining measurement precision, as the optical system objectively quantifies the interaction between air-entraining agents and carbonaceous materials without subjective human judgment.
2Quantity of substance
If activated carbon or unburned carbon is present in fly ash, then the adsorption capacity increases, but the air-entraining agent's ability to entrain air deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the optical measurement system continuously monitors the adsorption capacity of fly ash samples, and this information is used to adjust the dosage of air-entraining agents or sacrificial agents accordingly. By measuring fluorescence emission intensity and correlating it with adsorption capacity, the system provides real-time feedback that enables precise control of air void content in concrete, compensating for variations in carbon content and ensuring reliable air entrainment performance.
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 and real-time determination of fly ash adsorption capacity, ensuring optimal air void content in concrete and reducing frost damage susceptibility by providing a precise and automated solution for carbon passivation.
Implementation Method 1
The hydrophobic groups have the affinity to also adhere to activated carbon or unburned carbon introduced into the concrete by the fly ash. Hydrophobic groups that adsorb on carbon surfaces are not available to entrain air voids.
Implementation Method 2
measuring the intensity of fluorescence emission of the optically active sample
Data Source
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AI summary
A method and system for measuring the adsorption potential of fly ash. A sample of the fly ash is mixed with an optically active reagent. The mixture is irradiated with light at a given wavelength and an optical parameter of the irradiated sample, such as intensity of optical absorbance or fluorescence emission is measured by an optical measuring apparatus. The adsorption capacity of the sample is determined as a function of the optical measurement. The system comprises a controller that communicates with the optical absorption measuring apparatus and controls flow of fly ash and sacrificial agent to a reaction zone or housing wherein the fly ash is contacted by the sacrificial agent.