Cold Bituminous Mix Sequential Mixing Process

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Solution Overview

Problem

Cold hydrocarbon coatings face issues with reduced compactability and poor bitumen film distribution due to high viscosity binders at ambient temperatures, leading to inferior mechanical properties and stripping phenomena, especially with high fines content in granular fractions.

Innovation Solution

A process involving sequential mixing of solid mineral fractions with an emulsion binder, where the binder is initially applied without fluxing agents, followed by the addition of the remaining fluxing agent and additives, ensuring a sufficient ratio of mixing times to maintain binder distribution and cohesion without heating or reheating steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a high viscosity binder is used at ambient temperature in cold hydrocarbon coatings, then the binder provides structural stability, but the compactability of the mix is reduced and mechanical properties deteriorate

Engineering Contradiction:
Improvebinder structural stabilityVSAvoidmix compactability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the viscosity of the binder through the addition of fluxing agents. The fluxing agent content is controlled within specific ranges (1-20% for wearing courses, 10-40% for base courses) to reduce binder viscosity at ambient temperature, thereby improving compactability while maintaining structural stability. This resolves the contradiction by dynamically adjusting the viscosity parameter rather than using a fixed high-viscosity binder.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If fluxing or fluidizing agents are added to reduce binder viscosity for improved compactability, then the binder becomes more workable, but the distribution of the bitumen film over the granular fraction deteriorates

Engineering Contradiction:
Improvebinder workabilityVSAvoidbitumen film distribution
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies local quality by differentiating the treatment of binder based on the granular fraction size. The binder with fluxing agents is applied to coarse elements (d/D fraction) first, where lower viscosity is beneficial for coating. Then the same binder is applied to fine elements (0/d fraction), where the fluxing agent content is controlled to prevent excessive fluidity that would cause poor distribution. This localized approach resolves the contradiction by optimizing binder properties for each specific application context.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the granular fraction contains high fines content, then the mix achieves better packing density, but the distribution of binder over the granular fraction worsens due to fluxing agent effects

Engineering Contradiction:
Improvepacking densityVSAvoidbinder distribution
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the fluxing agent content based on the fines content in the granular fraction. For mixes with high fines content (up to 50% or more), the fluxing agent content is restricted to lower ranges (1-20% or even 1-10% in some embodiments) to prevent excessive binder fluidity that would cause poor distribution. This adaptive parameter adjustment resolves the contradiction by balancing packing density benefits against binder distribution requirements.

Inventive Principle:
Principle #35Parameter changes

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

This process achieves high-quality cold hydrocarbon coatings with improved compactability and cohesion, meeting standards like NF P 98-149, while minimizing energy consumption and avoiding stripping issues, even with high fluxing agent content.

Implementation Method 1

coat at room temperature all of the solid mineral fractions with an emulsion binder... which makes it possible to observe a coating of the coating

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

said binder comprising a fluxing or fluidizing agent... the fluxing or fluidizing content is high... the binder can be fluxed or fluidized by products of petroleum or vegetable origin

Methodology Applied
Scientific EffectFluxing:

Implementation Method 3

the quality of the coating can be poor, with the observation of a stripping phenomenon: poor distribution of the bitumen film over the entire granular fraction

Methodology Applied
Scientific EffectCoating: Coatings

Data Source

PatentEP2576911B1Process for manufacturing cold bituminous mixes, cold bituminous mixes with controlled workability and use thereof for producing road pavements
Publication Date: 2019.07.24 EUROVIA SA
  • EP2576911B1 patent drawingFigure 1A~1E

AI summary

The present invention relates to a process for producing cold bituminous mixes, comprising the following successive steps: a. in a mixer, coating, at ambient temperature, all of the solid mineral fractions with all of the binder in emulsion, and optionally a portion of fluxing agent, over a time interval T sufficient to observe a coating of the mix; then b. at the end of the time interval T, adding the remaining amount of fluxing agent, over a time interval t, such that the T/t ratio is greater than 2, the other mixing conditions of steps a) and b) being otherwise substantially identical. The present invention also relates to cold bituminous mixes, capable of being obtained by the process according to the invention and the use thereof for the production of wearing courses, the production of emulsion-stabilized gravels or the production of storage-grade mixes.