Material Definition and Product Properties

High-viscosity agents are a class of asphalt mixture modification additives designed primarily to enhance the dynamic viscosity of asphalt binders at 60°C. Typically appearing as spherical granules, these materials consist mainly of high-molecular-weight polymers and functional additives. They play a critical role in applications such as porous asphalt pavements, bridge deck pavements, and stress-absorbing layers. Compared to conventional asphalt modifiers, the technical approach of high-viscosity agents emphasizes dual mechanisms—physical blending and chemical grafting—to significantly enhance the cohesive properties and aggregate coating capacity of asphalt binders under high-temperature conditions.

Core Mechanism of Action

Based on research findings from fluorescence microscopy and infrared spectroscopy tests, high-viscosity agents primarily exert their effects in asphalt systems through two pathways:

First, physical blending effect. High-viscosity agent particles soften and melt at mixing temperatures, uniformly dispersing within the asphalt binder to form a polymer network structure. This network significantly increases the flow resistance of the asphalt system through molecular chain entanglement and interfacial adsorption, resulting in an order-of-magnitude increase in dynamic viscosity at 60°C.

Second, chemical modification. High-viscosity modifiers developed through grafting reactions—such as ethylene-methacrylic copolymers, polyketones, low-density polypropylene, and PTW resins—produce new absorption peaks in the asphalt system, indicating chemical bonding interactions between the modifier and asphalt components. This chemical modification endows the asphalt system with more stable performance retention capabilities.

Technical Specifications and Standard Framework

A clear technical specification framework has been established for high-viscosity asphalt. According to industry standards, high-viscosity asphalt used for porous asphalt pavements must meet a minimum dynamic viscosity requirement of 20,000 Pa·s at 60°C. Some high-performance products achieve measured values exceeding 300,000 Pa·s, with softening points above 75°C and 25°C penetration greater than 60 (0.1 mm). This established indicator system provides quantifiable technical basis for product R&D and engineering quality control of high-viscosity agents.

Composite Modification Technology Pathway

Single-component high-viscosity modifier modification suffers from limitations in performance dimensionality, making composite modification systems a key direction for technological advancement. Research indicates that high-viscosity composite modified asphalt prepared using 15% rubber powder, 1.5% reactive elastomer terpolymer (RET), and 9% high-viscosity modifier exhibits synergistic optimization in comprehensive performance. Compared to base asphalt mixtures, this composite system achieved a 3.46-fold increase in dynamic stability, a 23.3% rise in maximum flexural strain, and a 15.9% improvement in residual stability. This technical approach demonstrates that the combined use of multi-component modifiers can achieve balanced enhancements across multiple performance dimensions, including high-temperature rutting resistance, low-temperature crack resistance, and water stability.