Research On Hot Central Plant Recycling And Its Key Technologies Of Asphalt Pavement

About 90 percent of the highway built in our country is asphalt pavement, and almost would be in heavy repair period about 5 years later, which would leave a great deal reclaimed asphalt unused, not only waste resource but also lead fearful environment questions. The reused RAP can help us save energy sources, protect environment, and it is benefit to economy, society and environment.The objective of the thesis is to research the hot central plant recycling technology of waste asphalt mixture. Studying reused asphalt and RAP, confirm the compound proportion of RAP. Study on the key technologies of hot central plant recycling to form the design method of hot central plant recycling. By the means of theory analyzes and experiment research, material science and mechanical engineering, the paper drew a few conclusions as following:The paper advanced two methods for the reused asphalt based on analyzing the capability of RAP, they are adding new asphalt regeneration and adding recycling agent regeneration. when we use the new asphalt, the proportion of RAP was less than 30%. when we use the recycling agent, the best dosage of recycling agent was about 4%~5% of old asphaltAnalyzing the aggregate gradation of RAP, the paper figure out that aggregate of RAP was becoming thin and we need add new aggregate to improve the gradation. It studied the Marshall experiment's result in different proportion of RAP, found that the proportion of RAP could be increased to 50% when used the recycling agent. The paper advanced the estimate system of reused mixture performance, including the correcting formula of calculating theoretical maximum density and estimate guideline, which would found basis for the compound proportion of reused mixture in practice.The paper studied on the key technology of hot central plant recycling, and advanced the four segment design method of parallel-flow dryer drum, depending on different lamina structure to different section, and advanced the calculation method for the heat balance and the requirement to the control system, and bring forward estimate standard for the hot central plant recycling which provide design basis for plant recycling. By experiment research the paper provided some using and technics parameter for the hot central plant recycling, such as the hot gas safe temperature, the RAP hot up temperature, the RAP hot up time, mixture exceeding temperature, etc. they could offer warrant for producing eligible mixture.Sum up construction technics of hot central plant recycling at last, and construct experiment segment in practice, all examine result indicated there is no obvious difference between recycling and common asphalt pavement. Studies prove that it is effective according to the method, facility, and technics provide in the paper for recycling of RAP in logical design, which is in common to asphalt mixture and can satisfy demand in practice.