Bituminous Mixtures Using Recycled PVB Coating
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Solution Overview
Problem
Conventional bituminous mixtures for road paving and roofing face issues with non-homogeneity, environmental unfriendliness, and unpredictable mechanical properties due to the use of aggressive adhesion promoters and volatile solvents, as well as the lack of effective recycling of polymer waste.
Innovation Solution
A bituminous mixture comprising 2-8 wt% bitumen, 27-98 wt% mineral aggregates coated with a thermoplastic polymer composition of polyvinyl butyral (PVB), which is either virgin or recycled, along with optional inorganic fillers and smaller mineral aggregates, processed by heating and stirring to achieve uniform coating and improved mechanical properties without toxic adhesion promoters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If adhesion promoters are added to improve homogeneity of PVB in bitumen, then mixing homogeneity is improved, but environmental friendliness deteriorates due to toxic chemicals
Solution Approach 1:
The patent removes adhesion promoters and volatile solvents from the bitumen modification process. Instead of using chemical additives to achieve homogeneity, the invention uses physically mixed PVB particles with bitumen, where the polymer particles are dispersed throughout the bitumen matrix without requiring toxic adhesion promoters or solvents.
Solution Approach 2:
The patent changes the physical state and distribution parameters of PVB in bitumen. Rather than using dissolved PVB (which requires solvents), the invention uses suspended PVB particles that are distributed throughout the bitumen. This parameter change from dissolved to suspended state eliminates the need for toxic adhesion promoters while maintaining homogeneity.
2Stability of the object's composition
If volatile solvents are used to dissolve PVB for homogeneous mixing, then mixing homogeneity is improved, but environmental friendliness deteriorates due to out-gassing of toxic VOCs
Solution Approach 1:
The patent extracts and removes volatile solvents from the modification process. The invention achieves homogeneous mixing by physically dispersing PVB particles in bitumen without using any solvents, thereby eliminating VOC out-gassing while maintaining composition homogeneity throughout the product lifecycle.
Solution Approach 2:
The patent replaces expensive, environmentally harmful volatile solvents with simple, non-toxic physical mixing of PVB particles. This substitution uses inexpensive, environmentally benign materials and methods that do not require disposal or special handling, eliminating the harmful effects associated with solvent evaporation.
3Object-affected harmful factors
If recycled PVB is used to reduce waste, then environmental friendliness is improved, but mixing homogeneity deteriorates due to heterogeneous distribution
Solution Approach 1:
The patent applies preliminary action by pre-processing recycled PVB through size reduction and classification before mixing with bitumen. This preliminary preparation ensures that recycled PVB particles are of uniform, appropriate size for homogeneous dispersion, eliminating the heterogeneity problem while maintaining environmental benefits of recycling.
Solution Approach 2:
The patent changes the size distribution parameter of recycled PVB particles to achieve homogeneous mixing. By controlling particle size and distribution through preprocessing, the invention transforms heterogeneous recycled material into uniformly dispersed particles that mix homogeneously with bitumen, reconciling recycling benefits with composition stability.
4Strength
If thermoplastic polymer composition is used to coat aggregates, then mechanical properties are improved, but bitumen usage increases
Solution Approach 1:
The patent creates a composite material system where PVB-modified bitumen combines the adhesive properties of thermoplastic polymer with the binding properties of bitumen. This composite approach allows reduced bitumen content (2-8 wt%) while maintaining or improving mechanical properties through the synergistic interaction between PVB particles and bitumen matrix.
Solution Approach 2:
The patent changes the functional properties of bitumen by incorporating PVB particles, which enhance the binder's adhesive strength and mechanical performance. This parameter change in the binder's properties allows reduction of overall bitumen content in the mixture while maintaining required mechanical strength through the modified binder system.
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 results in bituminous mixtures with enhanced mechanical and environmental performance, reducing bitumen usage by up to 50% while maintaining or improving physical properties, and providing an environmentally friendly, cost-effective manufacturing process.
Implementation Method 1
mineral aggregates coated with a thermoplastic polymer composition
Implementation Method 2
processed by heating and stirring to achieve uniform coating
Data Source
AI summary
High performance bituminous mixtures that are useful for the road paving and roofing industries comprise mineral aggregates coated with a thermoplastic polymer composition. Because of their high performance properties, the absence of any aggressive and toxic adhesion promoters and the possibility of using recovered or recycled thermoplastic polymers to form the coating or 'membrane,' the bituminous mixtures described herein provide an excellent environmentally friendly solution for pavement construction and roofing industries.