Bioagent Separation of Bitumen from Siliceous Aggregates
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Solution Overview
Problem
Aging of bitumen in asphalt pavements leads to increased agglomeration of asphaltenes and reduced recyclability, making it difficult to separate and reuse bitumen from siliceous aggregates, resulting in reduced durability and increased moisture susceptibility of recycled materials.
Innovation Solution
A bioagent derived from hydrothermal liquefaction of swine manure and algae is used to separate and rejuvenate bitumen by disrupting hydrocarbon-siliceous stone interfacial bonds, forming a water-resistant bridge between bitumen and aggregates, thereby enhancing the recyclability and durability of bitumen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solvents are used to separate bitumen from siliceous aggregates, then separation efficiency is improved, but environmental toxicity and safety hazards increase
Solution Approach 1:
The invention changes the chemical parameters of the separation agent by using bio-oils with specific functional groups (polar oxygen and nitrogen heteroatoms) derived from renewable biomass through hydrothermal liquefaction. This substitution maintains separation efficiency while eliminating the toxicological parameters associated with conventional petroleum-based solvents like toluene and xylene.
Solution Approach 2:
The invention employs bio-oils derived from inexpensive, renewable biomass sources (swine manure and algae) that can be readily degraded in the environment. This replaces expensive, persistent, and toxic conventional solvents with cheaper, biodegradable alternatives that maintain functional effectiveness while reducing environmental harm.
2Loss of substance
If aged bitumen is reused in asphalt recycling, then material sustainability is improved, but separation difficulty from siliceous stones increases
Solution Approach 1:
The bio-oil acts as an intermediary substance that facilitates the separation of aged bitumen from siliceous aggregates. The polar functional groups in the bio-oil interact with both the aged bitumen and the siliceous surface, reducing the adhesion strength and enabling efficient separation. This intermediary mechanism overcomes the increased separation difficulty inherent in recycling aged materials.
Solution Approach 2:
The invention changes the interfacial parameters between aged bitumen and siliceous aggregates by introducing bio-oils with specific polar characteristics. This modifies the surface energy and adhesion properties at the interface, making the separation process feasible despite the aging-induced increases in viscosity and adhesion strength.
3Productivity
If bitumen is separated and reused, then recyclability is improved, but water-resistance and durability of recycled asphalt decrease
Solution Approach 1:
The bio-oil serves as a dual-function intermediary: it facilitates separation during recycling and simultaneously acts as a rejuvenating agent that restores the bitumen's protective properties. The polar functional groups in the bio-oil form a protective interface that enhances water-resistance, thereby maintaining reliability while improving recyclability.
Solution Approach 2:
The invention creates a composite system where bio-oil molecules are integrated with the bitumen matrix. This composite structure combines the bitumen's adhesive properties with the bio-oil's polar functional groups, resulting in a material that maintains both recyclability and enhanced water-resistance through the synergistic interaction of its components.
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 bioagent effectively separates bitumen from siliceous stones, rejuvenates aged bitumen, and improves its water-resistance, leading to enhanced durability and recyclability of bitumen, reducing the need for toxic solvents and improving the quality of recycled asphalt.
Implementation Method 1
A first role occurs due at least in part to a mechanism that includes attack of polar sites of bioagent to polar sites of silica and retreat of hydrocarbons from silica
Implementation Method 2
The bioagent facilitates separation of the aged bitumen in reclaimed asphalt from siliceous stones, and peptizes and rejuvenates the bitumen for reuse
Implementation Method 3
The bioagent can form a water-resistant bridge between the siliceous stone and the bitumen, thereby enhancing water-damage resistance of the revitalized bitumen
Implementation Method 4
The bioagent is typically derived from hydrothermal liquefaction of mixed biomasses. The resulting bioagent contains suitable functional groups in its molecular components that can disrupt the hydrocarbon-siliceous stone interfacial bonds
Data Source
AI summary
Treating aged asphalt includes contacting aged asphalt with a bioagent to yield a mixture. The aged asphalt includes a siliceous stone component and bitumen, and the bioagent includes bio-oils formed from hybrid biomasses. The siliceous stone component and the bitumen are separated. The bioagent promotes separation of the siliceous stone from the bitumen. A rejuvenated bitumen composition includes recycled bitumen, virgin bitumen, and a bioagent. The recycled bitumen can be produced from recycled asphalt paving, and the bioagent can include bio-oils formed from hybrid biomasses.