Modified Asphalt Composite Modifier Viscoelasticity
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Solution Overview
Problem
Current asphalt binders face challenges in achieving high viscosity and high elasticity simultaneously, which is crucial for advanced road construction and maintenance, particularly in ultra-thin asphalt structure systems and water-permeable pavements.
Innovation Solution
A modified asphalt is developed using a combination of styrene-butadiene-styrene block copolymer, rubber, and polyurethane as a modifier, along with a compatibilizer, sulfur, a non-amine anti-stripping agent, and a coupling agent, forming a three-dimensionally cross-linked structure to enhance viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high-viscosity modified asphalt is used, then viscosity index is improved, but elasticity index deteriorates
Solution Approach 1:
The patent uses a composite modifier system comprising SBS block copolymer, rubber powder, and polyurethane in specific ratios. This composite approach allows the asphalt to simultaneously achieve high viscosity (from SBS and polyurethane) and high elasticity (from rubber powder and the synergistic interaction of all three components), resolving the contradiction between viscosity and elasticity indices.
Solution Approach 2:
The patent optimizes the molecular weight parameters of the modifier components (SBS with Mn>200,000, polyurethane with Mn>10,000) and their ratios in the composite modifier. By controlling these parameters, the asphalt achieves both high viscosity and high elasticity, transforming the trade-off relationship into a coordinated improvement of both properties.
2Stability of the object's composition
If high-elasticity modified asphalt is used, then elasticity index is improved, but viscosity index deteriorates
Solution Approach 1:
The composite modifier system combines rubber powder (providing elasticity) with SBS and polyurethane (providing viscosity). This composite approach ensures that both elasticity and viscosity indices are simultaneously enhanced, eliminating the need to choose between the two properties.
Solution Approach 2:
The patent merges three different modifier components (SBS, rubber powder, polyurethane) into a unified modifier system. This merging allows the asphalt to inherit the elastic properties of rubber powder while simultaneously gaining the viscosity-enhancing effects of SBS and polyurethane, achieving dual high-performance characteristics.
3Stability of the object's composition
If multiple modifier components are combined, then viscoelastic properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary mixing of the three modifier components (SBS, rubber powder, polyurethane) before adding them to the asphalt. This preliminary preparation simplifies the overall manufacturing process by ensuring uniform distribution of components, reducing the complexity of the mixing operation, and facilitating better dispersion in the asphalt matrix.
Solution Approach 2:
The patent specifies particular properties for each modifier component (SBS with star-shaped structure and Mn>200,000, rubber powder with 40-100 mesh particle diameter, polyurethane with Mn>10,000). By controlling the local quality parameters of each component, the patent ensures optimal viscoelastic performance while maintaining manageable manufacturing complexity through standardized material specifications.
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 modified asphalt achieves high elastic recovery, dynamic viscosity, composite shear modulus, and thermal stability, meeting performance criteria such as ≥98% elastic recovery at 25°C, ≥500,000 Pa·s dynamic viscosity at 60°C, and ≥10 Pa composite shear modulus, with a critical temperature above 94°C.
Implementation Method 1
the modifier comprises a styrene-butadiene-styrene block copolymer, a rubber, and a polyurethane... which can form a three-dimensionally cross-linked structure after dissolved with the matrix asphalt
Implementation Method 2
subjecting the premix obtained in step (1) sequentially to shearing and swelling to obtain the first mix... subjecting the second mix obtained in step (3) sequentially to shearing, milling and development to obtain a modified asphalt
Data Source
AI summary
The modified asphalt provided by the disclosure is prepared from the following raw materials in parts by weight: 100 to 120 parts of asphalt, 6 to 20 parts of a modifier, 3 to 9 parts of a compatibilizer, 0.15 to 0.25 parts of sulfur, 0.4 to 0.6 parts of a non-amine anti-stripping agent and 0.2 to 0.4 parts of a coupling agent; and the modifier comprises a styrene-butadiene-styrene block copolymer, a rubber, and a polyurethane. The modified asphalt provided by the disclosure can simultaneously satisfy an elastic recovery at 25° C. of ≥98%, a dynamic viscosity at 60° C. of ≥500,000 Pa·s, a composite shear modulus at 60° C. of ≥10 Pa, and a critical temperature at G*/Sin≥2.2 kPa of ≥94° C.