Polyurethane Road Surface Layer for High-Temperature Strength
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Solution Overview
Problem
Existing road surface materials based on bitumen suffer from reduced strength at high temperatures, brittleness over time, and environmental concerns due to high energy consumption and CO2 emissions in production, as well as low load-bearing capacity and sensitivity to frost and aging.
Innovation Solution
A method using a mixture of mineral material and a polyurethane reaction mixture, which includes isocyanates, hydroxy-functional compounds, and optional additives, applied with a contact pressure of at least 5 N/cm² to create a durable and environmentally friendly surface layer that hardens without solvents, suitable for high-traffic areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bitumen-based surface layers are used, then ease of manufacture is improved, but strength at high temperatures deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the binder from bitumen to polyurethane reaction mixture, which fundamentally alters the temperature-dependent mechanical properties. The polyurethane system maintains its strength characteristics across a wider temperature range compared to bitumen, resolving the contradiction between ease of manufacture and high-temperature strength.
Solution Approach 2:
The patent creates a composite material system combining mineral aggregates with polyurethane reaction mixture. This composite approach allows the material to exhibit both the workability of organic binders and the thermal stability of polymeric systems, achieving high-temperature strength while maintaining ease of manufacture through cold application.
2Ease of manufacture
If bitumen-based surface layers are used, then ease of manufacture is improved, but durability over time deteriorates
Solution Approach 1:
The patent changes the chemical composition from bitumen to polyurethane reaction mixture, which fundamentally improves aging resistance. Polyurethane polymers do not undergo the same oxidative degradation and evaporation processes as bitumen, maintaining their binding properties and structural integrity over extended periods.
Solution Approach 2:
The patent employs a cold-applied polyurethane system that cures rapidly to form a durable surface layer, eliminating the need for high-temperature processing and extended curing times associated with traditional bitumen applications.
3Strength
If bitumen mixtures are produced at high temperatures, then viscosity is reduced for proper wetting, but energy consumption increases
Solution Approach 1:
The patent changes the temperature parameter from high (180°C) to ambient or cold conditions by using a polyurethane reaction mixture with inherently lower viscosity at room temperature. This eliminates the need for energy-intensive heating while ensuring proper wetting of aggregate particles through the chemical reactivity of the polyol and isocyanate components.
Solution Approach 2:
The patent replaces the thermal energy input system with a chemical reaction system. Instead of using heat to reduce viscosity, the polyurethane components react chemically at ambient temperatures to form a binding matrix that wets and binds aggregates effectively without requiring external energy input.
4Strength
If bitumen mixtures are produced at high temperatures, then viscosity is reduced for proper wetting, but CO2 emissions increase
Solution Approach 1:
The patent changes the temperature parameter from high (180°C) to ambient conditions, eliminating the combustion of heating oil and associated CO2 emissions. The polyurethane reaction mixture achieves proper viscosity and wetting properties through its chemical composition rather than thermal energy input.
Solution Approach 2:
The patent replaces the thermal processing system with a chemical reaction system that occurs at ambient temperatures. The polyol and isocyanate components react to form polyurethane polymers that bind aggregates effectively without requiring fossil fuel combustion, thereby eliminating CO2 emissions associated with heating.
5Strength
If polyurethane reaction mixture is used, then load-bearing capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the polyurethane system into separate components (polyol and isocyanate) that are mixed immediately before application. This segmentation allows each component to be stored and handled separately under simple conditions, while the final mixture provides the desired load-bearing capacity through in-situ polymerization.
Solution Approach 2:
The patent replaces complex high-temperature mixing and processing equipment with simple cold-apply mixing devices. The chemical reactivity of the polyurethane components enables thorough mixing and bonding without requiring sophisticated mechanical systems, thus achieving high load-bearing capacity with minimal manufacturing complexity.
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 provides a surface layer with high load-bearing capacity, resistance to aging and freeze-thaw cycles, and reduced environmental impact, maintaining mechanical properties over time with improved slip resistance and reduced hydrolytic degradation.
Implementation Method 1
a polyurethane reaction mixture, which includes isocyanates, hydroxy-functional compounds
Implementation Method 2
the reaction mixture is obtained by mixing (a) isocyanates with (b) compounds having at least two hydrogen atoms reactive towards isocyanate
Implementation Method 3
applied with a contact pressure of at least 5 N/cm² to create a durable and environmentally friendly surface layer
Implementation Method 4
the mixture containing mineral material and a polyurethane reaction mixture... is cured
Implementation Method 5
hardens without solvents
Data Source
AI summary
The present invention relates to a method for producing cover layers for roads, streets, and other traffic surfaces, wherein a mixture, containing mineral material and a polyurethane reaction mixture, and optionally further additives, is produced, applied to an underlying surface material, compacted using a contact pressure of at least 5 N/cm2, and cured, the work being performed substantially without the use of solvents. Furthermore, the present invention relates to cover layers for roads, streets, and other traffic surfaces, obtainable according to such a method.