Bi-component synthetic fibers for cement reinforcement
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Solution Overview
Problem
Conventional steel and glass fibers used for reinforcing concrete have limitations such as corrosion, poor dosing and mixing properties, and limited alkali resistance, while synthetic fibers face challenges in achieving high tensile strength and bond strength with concrete, leading to inadequate ductile behavior and energy absorption.
Innovation Solution
Development of bi-component plastic fibers with a core and sheath structure, where the sheath is optimized for bond strength and processability, and the core for tensile strength, using polymers with different melt flow rates and molecular weight distributions, and incorporating nanoparticles for enhanced embossing and chemical modification to improve mechanical properties and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel fibers are used for reinforcing concrete, then tensile strength and ductile behavior are improved, but corrosion resistance deteriorates and manufacturing complexity increases
Solution Approach 1:
The patent uses composite materials by combining polymer fibers with mineral additives (such as silane-modified polymers, metal oxides, or ceramic particles) to create synthetic fibers that exhibit both high tensile strength and corrosion resistance. The composite structure allows the polymer matrix to provide flexibility and tensile properties while the mineral additives enhance strength and provide resistance to chemical degradation and corrosion.
2Strength
If steel fibers are used for reinforcing concrete, then tensile strength is improved, but ease of operation deteriorates due to poor dosing and mixing properties
Solution Approach 1:
The patent employs short synthetic fibers (typically 6-12 mm in length) made from polymer materials that are inexpensive and easily handled. These short fibers can be freely dispersed in concrete mixtures without the handling complexities of long steel fibers, allowing for simple dosing and mixing operations while still providing effective reinforcement through their high surface-area-to-volume ratio.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the reinforcement fibers by using polymer materials with optimized molecular weight, melt flow rate, and surface properties. These parameter changes result in fibers that have improved flow characteristics, better distribution in concrete, and easier dosing compared to steel fibers, while maintaining adequate tensile strength through composite formulation.
3Strength
If glass fibers are used for reinforcing concrete, then tensile strength is improved, but alkali resistance deteriorates
Solution Approach 1:
The patent employs composite materials by combining polymer fibers with mineral additives (such as silane-modified polymers, metal oxides, or ceramic particles) to create synthetic fibers that exhibit both high tensile strength and corrosion resistance. The composite structure allows the polymer matrix to provide flexibility and tensile properties while the mineral additives enhance strength and provide resistance to chemical degradation and corrosion.
4Quantity of substance
If polyolefin fibers are used for reinforcing concrete, then cost is reduced, but modulus of elasticity and bond strength deteriorate
Solution Approach 1:
The patent uses composite materials by combining polymer fibers with mineral additives (such as silane-modified polymers, metal oxides, or ceramic particles) to create synthetic fibers that exhibit both high tensile strength and corrosion resistance. The composite structure allows the polymer matrix to provide flexibility and tensile properties while the mineral additives enhance strength and provide resistance to chemical degradation and corrosion.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the reinforcement fibers by using polymer materials with optimized molecular weight, melt flow rate, and surface properties. These parameter changes result in fibers that have improved flow characteristics, better distribution in concrete, and easier dosing compared to steel fibers, while maintaining adequate tensile strength through composite formulation.
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
The bi-component fibers achieve improved tensile strength, bond strength, and ductile behavior in concrete, reducing material waste and costs, with enhanced handling and mixing properties, and providing a more homogeneous molecular structure and increased modulus of elasticity, leading to better performance and durability compared to traditional fibers.
Implementation Method 1
the core consists of polymers with a low MFR and a very narrow molecular weight distribution, and whose sheath consists of polymers with a higher MFR and a broad molecular weight distribution... the sheath still has sufficient reserves to reliably fix the fiber and thereby prevent fibrillation under load
Implementation Method 2
The embossing process creates grooves in the embossed part and at the same time the plastic is displaced laterally, which also causes a laterally structured surface, which then has a positive effect on the adhesion of the cement to the fibers and their interlocking with the concrete
Implementation Method 3
The sheath of the bi-component fibers presented here consists of modified polymers that are optimized in terms of adhesion to cement and processing properties
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The core/shell fibre is made from plastics such as polypropylene, polyethylene or a mixture of said raw materials or other thermoplastic polymers. The fibre diameter is 0.15 to 2.0 mm and the core/shell fibre has a completely- or intermittently-structured surface, generated by embossing (5) which is carried out on a single side or multiple sides, the depth of which is at least 10 % of the average fibre diameter. The embossing (5) can be perpendicular or diagonal or in any form with relation to the fibre direction, but in any case is increased by a factor of 5 to 15 after drawing the fibre. The core/shell fibre is cut in sections of 10 to 80mm and collected in bundles of several thousand and wound in a water-soluble plastic film. Said fibres are used to increase the tensile strength, to improve the crush resistance or generally for mechanical reinforcement of cement-bonded building materials, in particular in concrete. The bundles can be incorporated together with the plastic film in the building material with no disadvantages.