In recent years, my country's highway construction has boomed. Asphalt pavement, due to its superior driving comfort and performance, has become the preferred material for highway pavements. However, traditional hot-mix asphalt technology leads to severe environmental pollution and energy consumption during construction. Faced with this challenge, scientists are committed to developing environmentally friendly construction methods, leading to the emergence of warm-mix asphalt technology. This technology effectively lowers the mixing and paving compaction temperatures of the asphalt by adding a warm-mix agent during the hot-mixing process, thereby reducing smoke emissions and saving energy. The warm-mix agent reduces the viscosity of asphalt at high temperatures, improving its fluidity, thereby achieving the goal of lowering construction temperatures without compromising the asphalt's road performance.

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1. Overview of Warm-Mix Asphalt Technology
1.1 Technical Background
The traditional hot-mix asphalt method, widely used in asphalt pavement construction, has numerous problems, primarily the generation of large amounts of pollutants during construction, posing a threat to the environment and human health. This has driven the development of an environmentally friendly construction method, namely warm-mix asphalt technology. 1.2 Types and Challenges of Warm-Mix Agents
Currently, there are three main types of warm-mix technologies on the market: organic viscosity reduction, foamed asphalt viscosity reduction, and emulsified dispersed asphalt viscosity reduction. However, these technologies face challenges such as high equipment costs and compatibility issues. Although my country has made some progress in warm-mix agent research, product performance still needs to be improved. Developing cost-effective warm-mix asphalt is an urgent need for the development of road construction in my country.
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2. Research on Warm-Mix Agents for Asphalt
2.1 Function and Mechanism of Warm-Mix Agents
The warm-mix agent for asphalt used in this study is a white powder that is easy to add and inexpensive. When preparing warm-mix asphalt, only 1-3% of the base asphalt needs to be added. This warm-mix agent effectively reduces asphalt viscosity and improves its low-temperature ductility, providing a new solution to addressing the low-temperature performance issues of warm-mix asphalt. The components of this warm-mix agent work synergistically. The addition of rubber powder optimizes the effect of fatty acids on the low-temperature performance of asphalt, which helps alleviate the increase in asphalt viscosity caused by the addition of rubber powder. Furthermore, the addition of ethylene bisstearamide and ethylene bisoleamide not only mitigates the effects of fatty acids on the asphalt softening point but also promotes uniform swelling of rubber crumb in the asphalt, thereby mitigating thermal aging during the rubber crumb modification process. Furthermore, these two additives enhance the dispersibility of the various components, further reducing the asphalt's viscosity at 135°C.
2.2 △ Application Effects of Warm-Mix Admixture
This warm-mix admixture effectively reduces asphalt mixing, paving, and compaction temperatures, overcoming the environmental pollution, high energy consumption, and asphalt aging issues associated with traditional processes. It exhibits a significant viscosity-reducing effect, not only addressing the low-temperature ductility issues of existing warm-mix asphalt, but also significantly improving its low-temperature performance. The preparation and application of this warm-mix admixture are simple and easy. Warm-mix asphalt prepared using this warm-mix admixture exhibits a low viscosity at 135°C, while exhibiting an increase in viscosity at 80°C. This type of asphalt maintains excellent mixing, paving, and compaction properties even at lower construction temperatures, significantly reducing energy consumption, emissions of harmful gases and dust, and effectively preventing thermal aging and performance degradation of warm-mix asphalt during the mixing process. Furthermore, this warm-mix asphalt exhibits significantly improved low-temperature ductility and softening point, further enhancing its high-temperature stability and low-temperature crack resistance.
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3. Development of Modified Warm-Mix Admixtures
3.1 △ Technical Performance Improvements
As an energy-saving technology, warm-mix asphalt technology can achieve performance comparable to or approaching that of hot-mix asphalt. By adopting this technology, temperatures can be reduced by 20-30°C, resulting in energy savings of over 20%. Furthermore, it improves the flowability of the asphalt mixture, lowers storage temperatures, and reduces emissions.
3.2 △ Key Directions for Future Development
Currently, mainstream warm-mix admixtures on the market are mostly improvements on traditional warm-mix admixtures, but their asphalt modification effects are still limited. Improving key performance indicators such as low-temperature ductility, high-temperature softening point, and penetration has become a key direction for the future development of warm-mix admixture technology. By improving the existing warm mix admixture formula, we have successfully reduced the viscosity of the asphalt mixture and significantly improved its anti-stripping performance. This also effectively reduces application temperatures and fuel consumption. The recommended addition level of this warm mix admixture is 2-5% of the base asphalt.