Rubber Asphalt Using Hexanediol Crosslinking

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Solution Overview

Problem

Existing rubber asphalt technologies require a large amount of asphalt, result in high costs, and have complex processes with strict quality control, leading to reduced flowability and increased adhesiveness, making them uneconomical and environmentally polluting.

Innovation Solution

A rubber asphalt composition with a higher content of waste tire powder and hexanediol as a crosslinking agent, allowing for a reduced asphalt-aggregate ratio and improved flowability while maintaining adhesiveness, using a simplified wet mixing process that avoids desulfuration and melting steps, utilizing a ratio of 4-1 matrix asphalt to rubber modifier and 94-96 waste tire powder to hexanediol, and heating to 190-210°C to produce a more penetrable and cost-effective product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the content of rubber powder is increased to improve pavement performance, then the adhesiveness of rubber asphalt is increased, but the flowability is reduced and construction workability is reduced

Engineering Contradiction:
ImproveadhesivenessVSAvoidflowability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific crosslinking agents (metal salts, organic compounds, or their combinations) and controlling their content (0.1-5% of rubber powder mass). This chemical modification enables the rubber powder to achieve both high adhesiveness and acceptable flowability, resolving the contradiction between these two properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system by combining rubber powder with crosslinking agents and optional助agents in specific ratios. This composite approach allows the rubber-modified asphalt to simultaneously exhibit enhanced adhesiveness from rubber powder and maintained flowability through the chemical action of crosslinking agents, thus resolving the contradiction.

Inventive Principle:
Principle #40Composite materials

2Strength

If the content of rubber powder is increased to improve pavement performance, then the adhesiveness is improved, but the construction cost is increased due to high asphalt requirement

Engineering Contradiction:
ImproveadhesivenessVSAvoidasphalt usage
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent modifies the chemical parameters of the rubber modification system by adding crosslinking agents that enable effective rubber-asphalt interaction at lower rubber powder contents (5-30% by weight). This chemical enhancement reduces the need for excessive asphalt to achieve adequate adhesiveness, thereby reducing overall material costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs inexpensive crosslinking agents (metal salts, organic compounds) that can be added in small quantities to achieve significant performance improvement. These low-cost additives replace the need for large amounts of expensive asphalt, thus reducing the quantity of substance required while maintaining adhesiveness.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If the existing rubber asphalt process is used with strict quality control, then the adhesiveness is improved, but the process complexity is increased and environmental pollution is caused

Engineering Contradiction:
ImproveadhesivenessVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex desulfuration step from the traditional rubber modification process. By using crosslinking agents that work directly with raw or minimally processed rubber powder, the method removes the need for sulfur removal equipment and complex multi-stage processing, thereby reducing device complexity while maintaining adhesiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the traditionally harmful sulfur content in rubber powder from a nuisance requiring complex removal into a beneficial component. The crosslinking agents utilize the sulfur in rubber to form crosslinked structures that enhance adhesiveness, thus eliminating the need for desulfuration equipment and reducing process complexity while improving performance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Strength

If the existing rubber asphalt process is used with strict quality control, then the adhesiveness is improved, but the environmental pollution is increased

Engineering Contradiction:
ImproveadhesivenessVSAvoidenvironmental pollution
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the environmentally problematic desulfuration process into a beneficial crosslinking process. By using crosslinking agents that react with rubber components in a controlled manner, the method eliminates the need for harsh desulfuration chemicals and high-temperature processing that cause pollution, while still achieving high adhesiveness.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent removes the polluting desulfuration step from the production process. By directly using rubber powder with crosslinking agents, the method eliminates the generation of harmful byproducts and reduces environmental pollution while maintaining the required adhesiveness performance.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method increases the use quantity of rubber powder modifier, reduces asphalt usage, enhances penetrability, and balances adhesiveness and flowability, meeting industrial standards with improved pavement performance and reduced environmental impact.

Implementation Method 1

hexanediol as a crosslinking agent

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

heating to 190-210°C to produce a more penetrable and cost-effective product

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentUS8912241B2Rubber asphalt and preparation method thereof
Publication Date: 2014.12.16 SICHUAN GAIRUI NEW MATERIAL TECH CO LTD

AI summary

A rubber asphalt and a preparation method thereof are disclosed. The rubber asphalt comprises matrix asphalt and rubber powder modifier in a ratio of 4:1-4, wherein the rubber powder modifier comprises waste tire rubber powder and hexanediol in a ratio of 94-96:6-4. The method comprises the following steps: mixing the hexanediol with the waste tire rubber powder according to the ratio and stirring and wetting to obtain the rubber powder modifier; placing the matrix asphalt into a reaction kettle and heating to 90-170° C.; adding the rubber powder modifier into the reaction kettle according to the ratio; and raising the temperature to 190-210° C. under the stirring state to obtain the rubber asphalt. The rubber asphalt has an extensibility of 13-19 cm at 5° C., a penetration of 68-75 at 25° C. and a softening point of 53-90° C. The asphalt-aggregate ratio of a mixed material on the subsequent work section can be reduced to 6-8 from 8-10. The rubber asphalt can be used for producing a mixture for highway construction and preventing water and leakage of roofing and tunnel.