Sterol Blends for Asphalt Binder Aging Resistance

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Solution Overview

Problem

Asphalt pavement deteriorates over time due to aging, leading to loss of flexibility, oxidation, brittleness, and cracking, especially under stress or at low temperatures, which limits the reuse of recycled asphalt.

Innovation Solution

The use of a pure sterol:crude sterol blend with a weight ratio of 10:90 to 90:10 added to asphalt binder compositions, including virgin and aged asphalt binders, to retard or reduce the effects of aging and restore some original properties of virgin asphalt.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If softening agents are added to virgin binder to restore acceptable binder properties after aging, then binder flexibility and low-temperature properties are improved, but mixture stiffness during early pavement life deteriorates

Engineering Contradiction:

Improvebinder properties stabilityVSAvoidmixture stiffness

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by incorporating sterol blends (comprising sterols and stanols) into the asphalt binder. This chemical modification allows the binder to maintain appropriate stiffness during early pavement life while still providing flexibility and preventing cracking during aging, thereby resolving the contradiction between initial stiffness and long-term flexibility without requiring softening agents

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite approach by combining sterols and stanols in a blend formulation within the asphalt binder system. This composite material approach enables simultaneous achievement of multiple performance characteristics: sufficient initial stiffness for pavement strength and adequate flexibility for crack prevention, eliminating the need for separate softening agents that would compromise stiffness

Inventive Principle:

Principle #40Composite materials

2Productivity

If recycled asphalt pavement is used in sub-surface layers or controlled amounts, then material reuse and cost reduction are improved, but long-term performance deteriorates due to aging effects

Engineering Contradiction:

Improverecycled material usageVSAvoidlong-term performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies the chemical parameters of the asphalt binder by adding sterol blends, which changes the aging characteristics of the binder. This parameter change slows the oxidation and brittleness development that normally occur with recycled asphalt, thereby maintaining long-term performance reliability while enabling broader use of recycled materials in various pavement layers

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sterol blend acts as an intermediary substance that mediates between the degraded properties of recycled asphalt and the performance requirements of the pavement. The sterols and stanols in the blend provide a protective effect that reduces the negative impact of aging on recycled asphalt, allowing recycled materials to achieve both high reuse rates and maintained long-term performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12234189B2Sterol blends as an additive in asphalt binder

Publication Date: 2025.02.25 ALM HOLDING CO

AI summary

Disclosed are asphalt binder compositions and methods for making such compositions with pure sterol:crude sterol blends. The sterol blends improve various rheological properties.