Design Method and Evaluation Criteria on Gyratory Compaction Based Cold-Mixed and Cold-Laid Recycled Asphalt Mixture

Cold-mixed recycled asphalt mixture is widely used due to the advantages of good eco-friendliness, resource conservation, and convenient construction. In order to further improve the mixing ratio design theory of cold-mixed recycled mixture, this paper has presented the research on design method and evaluation criteria of cold-mixed and cold-laid recycled asphalt mixture based on gyratory compaction. Research has shown that fine aggregate and mineral powder adhere to asphalt and exist in the form of agglomeration in the Reclaim Asphalt Pavement (RAP), which will cause the gradation of the milling plan material to decay after extraction. According to the viscosity characteristics of cold mixed asphalt, it is recommended that the mixing temperature of the mixture should be greater than 25°C, the compaction of cold-mixed recycled mixtures is easier to achieve by using gyratory compaction method. The paper proposes a test method to determine the optimal asphalt content based on initial strength and sweep test, and proposes a test method for controlling the strength of the mixture by the number of compactions and the forming temperature, establishes evaluation system of initial strength and final strength of cold-mixed recycled mixture, and corrects the evaluation method of high temperature stability and water stability of cold-mixed recycled mixture. The results show that the cold-mixed recycled mixture has low initial strength, insufficient high-temperature stability and water stability. With the volatilization of the diluent, the strength, high temperature stability and water stability of the mixture have been significantly improved.