Research On Application Performance Evaluation Of Varied Mechanism Warm Mix Asphalt

Because of lots of advantages, such as comfortable driving, easy maintenance and so on, Asphalt Concrete Pavements have been making a significant contribution to Chinese highway construction business in recent years. December2011, the second commitment period of the Kyoto Protocol through the World Climate Conference in Durban. And with the requirements of energy saving and emission reduction in China’s "12th Five-Year Plan", the highway asphalt concrete pavement have been suffering a great impact due to the high energy consumption and pollution. Generally, Hot Mix Asphalt is used in asphalt-pavement construction. The temperature of blending is high as to175℃, which is results in high energy and emissions directly. And the generated asphalt smoke and other harmful gases endanger the staff’s physical seriously. Recently, Warm Mix Asphalt has been used widely. Many studies and practices around the world showed that it can greatly reduce the temperature of the mixture construction and the energy consumption and harm.However, application performance evaluation of Warm Mix Asphalt is faultiness. So that construction temperatures are mostly based on the experience and traditional evaluation methods. And the economic evaluation still remains at the qualitative level. Therefore, the evaluation of Warm Mix Asphalt is improved in this paper, including the construction temperature, pavement performance and economic evaluation. Four different Warm Mix Additives’mechanisms are deeply researched. Using a serious of tests with nified mix propotion and materials, the author desighes the Penetration Test to evaluate construction performance of asphalt mixture. Traditional methods are used to evaluate the pavement performance and the economic evaluation is calculated quantitatively.Because the reasonable temperature influences the mixture" workability directly, the key of construction performance is the construction temperature. In this paper, after analysing the shearing resistance and its impact factors, the author consider that the shear capacity is only related the asphalt’s viscosity. And the mechanisms of warm mix additives are to reduce the viscosity. Therefore, this paper proposes the Penetration Test first to determine the construction temperature of asphalt mixture and inventes the penetration device. Based on Penetration Test, the construction temperatures of the four Warm Mix Asphalts are determined. And then, the author uses the gyratory compactor (SGC) to verify the science and applicability of the Penetration Test with the indicator of Porosity. The results show that the different mechanism of warm mix technologies all can reduce the construction temperature. The amount ranges from10℃to20℃, which are different from manufacturer’s data slightly.For the pavement performance of Warm Mix Asphalt, this paper use traditional methods (wheel tracking test, low temperature trabecular test and freeze-thaw splitting test) to evaluate the high-temperature stability, low-temperature anti-cracking and water stability under the construction temperature determined by Penetration Test. The four Warm Mix Asphalts’ pavement performances are different to another and better than Hot Mix Asphalt.In this paper, rigorous quantitative evaluations are used to calculate the social and economic benefits of Warm Mix Asphalt. And Life Cycle Cost is introduced. The author considers the effect of energy saving and emission reduction is remarkable. The hazards of asphalt mixture on environment and human are reduced greatly and the effectiveness is obvious.This paper introduces pavements with different Warm Mix Additives.