Polymer Microfibre Content Determination in Cement Composites
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Solution Overview
Problem
There is a lack of standardized testing methods for determining the content of polymer microfibres in cement composites, such as concrete and mortar, particularly for microfibres with diameters less than 0.30 mm, which are crucial for assessing their reinforcement effectiveness.
Innovation Solution
A method utilizing the buoyancy phenomenon, where a cement composite sample is crushed and flooded with a liquid of intermediate density, allowing microfibres to float and be collected, followed by the sequential addition of an inorganic acid to release bound microfibres, with subsequent collection and ignition to separate and weigh the microfibres, thereby determining their content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If conventional washing or sieving methods are used to separate fibres from concrete, then macrofibres can be removed, but polymer microfibres with diameter less than 0.30 mm cannot be separated
Solution Approach 1:
The method changes the separation parameter from mechanical (sieving) to density-based (buoyancy). By using a liquid with density between that of microfibres and cement matrix, microfibres are selectively separated through buoyancy, enabling accurate detection and measurement of microfibre content in concrete samples.
2Reliability
If no standardized testing method exists for polymer microfibres, then research can proceed freely, but reliable data on microfibre content cannot be obtained
Solution Approach 1:
The method uses the natural buoyancy property of microfibres to achieve self-separation without requiring complex external equipment. The liquid density is carefully selected to enable automatic separation during mixing, providing reliable data while maintaining operational simplicity and potential for standardization.
3Strength
If microfibres are bound to cement matrix, then reinforcement is achieved, but separation becomes difficult
Solution Approach 1:
The liquid with intermediate density acts as an intermediary medium that facilitates separation. It allows bound microfibres to be released from the cement matrix through buoyancy forces, enabling easy separation while preserving the reinforcement effectiveness achieved during the concrete's strength development.
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
This method enables accurate determination of microfibre content in cement composites, providing reliable data on their presence and quantity in concrete or mortar samples.
Implementation Method 1
a cement composite sample containing microfibres is crushed to grains less than 1 mm in size, the crushed mixture is flooded with a liquid with a density greater than that of the microfibres, but less than the density of a cement matrix, and after mixing and sedimentation the microfibres are collected from the surface
Implementation Method 2
after collection of microfibres a portion of an inorganic acid (including but not limited to, e.g., hydrochloric, nitric, sulphuric, phosphoric acid) is added to the liquid to set free any microfibres bound to the cement matrix
Implementation Method 3
in case they are contaminated, they are additionally ignited at the polypropylene decomposition temperature, as a result of which the microfibres will decompose and only impurities remain whose weight after weighing is subtracted from the dried microfibres
Data Source
AI summary
The present application relates to a method of determining the content of polymer microfibres in cement composites based on the utilisation of the buoyancy phenomenon. The method is characterized in that a cement composite sample containing microfibres is crushed to grains less than 1 mm in size, the crushed mixture is flooded with a liquid with a density greater than that of the microfibres, but less than the density of the cement matrix, and after mixing and sedimentation the microfibres are collected from the surface, whereupon a portion of an inorganic acid is added to the solution to set free any microfibres bound to the cement matrix, and after mixing additional microfibres are collected from the surface, wherein the addition of acid and collection of microfibres operations are repeated until no microfibres come up to the surface, and then the microfibres thus separated are dried and weighed, and in case they are contaminated, they are additionally ignited at the polypropylene decomposition temperature, as a result of which the microfibres will decompose and only impurities remain whose weight after weighing is subtracted from the dried microfibres, and the final result obtained will indicate the content of microfibres in the tested sample.