Hot Central Plant Recycling Technology Of Asphalt Pavement

With the freeway volumes and load's fast increasing, some freeways should be maintained and reconstructed in succession. As a result, a mass of old asphalt mixture will be produced. The materials were discarded in the past years. This resulted in an enormous waste of resources and occupied vast expanses of land as well. The adoption of hot central plant recycling technology will reutilize pavement materials, and also be a burning issue lying before the researchers and engineers. Based on researches, results from home and abroad, and combined with the project "the central plant recycling technology study"of freeway mass-reconstruction from Guangzhou to Foshan, the paper studies the performance of old asphalt mixture, asphalt recycling mechanism, and the performance of hot recycled mixture. Firstly, the paper analyzes the technological characteristics of old asphalt mixture through in-site investigation and tests. Secondly, through infrared adsorption analysis and asphalt theory, the paper analyzes the mechanism of asphalt aged and recycled. New asphalt of AH-70 concoct old asphalt under the prerequisite of controlling the proportion of RAP. Many tests show that the recycled asphalt has good road character and the approach is feasible. Thirdly, the physical and mechanical properties of the recycled mixture are studied in the paper by means of indoor experiments. The changing laws of the road character indexes are related to the designed penetration and asphalt content allowable deviation of hot recycled mixture are established. It confirms that the range of the designed penetration of hot recycled mixture is from forty to sixty and the range of asphalt content allowable deviation of hot recycled mixture is from –0.3% to 0.4%. It proposes design method and evaluation standard of hot recycled mixture. The performance of hot recycled mixture has been studied by many tests. The test results show that the performance of hot recycled mixture have not more deference than the performance of new asphalt mixture. Fourthly, based on the freeway project, construction techniques of hot recycled mixture have been probed into. Finally, the paper analyzes the technique property, economical and social result of hot recycled mixture of asphalt pavement. It indicates that hot central plant recycling technology is a favorable method for freeway maintenance and reconstruction　and especially should be applied in the region where is scarce of aggregate.