Polyurethane Binder Road Surfacing Composition Noise Reduction
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Solution Overview
Problem
Current road surfacing materials fail to adequately reduce traffic noise and maintain durability, leading to frequent repairs and increased noise levels over time.
Innovation Solution
A road surfacing composition comprising hard particles and a two-component polyurethane binder system with a crosslink density between 0.1 and 2 mmoles/cm³, providing porosity of at least 10% and a low binder volume percentage, which enhances noise reduction and durability without relying on elastic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If porous road surfacing compositions with polymeric binders are used to achieve water permeability, then water permeability is improved, but noise reduction and durability of mechanical and acoustic properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by using a specific two-component polyurethane system with defined crosslink density (0.1-2 mmoles/cm³) and molecular weight characteristics. This parameter optimization allows the binder to maintain adequate adhesion in porous structures while achieving both noise reduction and durability simultaneously
Solution Approach 2:
The patent creates a composite material system combining hard aggregate particles with a specifically formulated two-component polyurethane binder. The composite achieves synergistic effects where the binder's controlled crosslinking provides durability while the porous structure enabled by the binder system provides water permeability and noise reduction
2Object-generated harmful factors
If elastic aggregate (rubber chips) are added to reduce noise generation, then noise reduction is improved in fresh road surfacing, but durability deteriorates and frequent repairs are needed
Solution Approach 1:
The patent extracts the elastic aggregate (rubber chips) from the road surfacing composition entirely. Instead of using elastic particles for noise reduction, the invention relies on the porous structure of the composition and the specific polyurethane binder system to achieve noise reduction without compromising durability
Solution Approach 2:
The patent replaces the durable but noisy conventional asphalt with a porous polyurethane-based composition that achieves noise reduction through its structure rather than through elastic particles, eliminating the need for frequent repairs associated with elastic aggregate formulations
3Strength
If high binder volume percentage is used to ensure durability, then binding strength is improved, but porosity and water permeability deteriorate
Solution Approach 1:
The patent optimizes the binder volume to less than 80, 70, 60 or 50% (preferably less than 40, 30 or even 20%) of the total bulk free volume of the hard particles. This parameter optimization, combined with the specific crosslink density control, achieves adequate binding strength while maintaining high porosity for water permeability
Solution Approach 2:
The patent utilizes a porous material structure enabled by the controlled binder volume and the specific polyurethane binder system. The porous structure provides water permeability and noise reduction while the binder's crosslinking provides sufficient binding strength
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 solution achieves significant noise reduction of up to 9.5 dB compared to dense asphalt concrete, maintains durability, and allows for quicker traffic access due to rapid compressive strength development, while being more resistant to water pressure and chemical washes.
Implementation Method 1
a two-component polyurethane binder system P which after curing has a crosslink density X, defined as the number of moles of elastically effective network chains per volume, between 0.1 and 2
Implementation Method 2
have desirably a high porosity in view of water permeability
Data Source
AI summary
The invention relates to a road surfacing composition for the preparation of a silent and water-permeable road surfacing comprising hard particles A, a two-component polyurethane binder system which after curing has a crosslink density X, defined as the number of moles of elastically effective network chains per volume, between 0.1 and 2 mmoles/cm3, said road surfacing composition having a porosity of at least 10% and preferably comprises: a) 80 - 98 wt% of a hard particles A, b) 2 - 20 wt% of the polyurethane binder, c) 0 - 10 wt% additives other than a) or b), the sum of wt% of a) to c) being 100 wt%.