2369 / Experimental Verification Of Particle Behavior During Crushing And Mixing Of Deteriorated Asphalt Pavement Layers By Stabilizer

Authors

Takatomo Fujii, Takashi Kurosu, Osamu Oikawa, Takashi Okayasu, Toyohiro Katou, Yuta Hirayama, and Yukinori Tsukimoto

Paper presented at ISTVS 2024 | 21st International and 12th Asia-Pacific Regional Conference of the ISTVS Keywords: Road stabilizer; Experimental verification; Reclamation; Crushing and mixing behavior; Three-dimensional discrete element method (3D-DEM); Particle size distribution https://doi.org/10.56884/2VEBGCMK

Abstract

In the road-subbase reclamation method, a stabilizer's rotor bits (teeth) are rotated to crush deteriorated asphalt pavement in-situ while mixing it with additives such as cement and asphalt emulsion, which are then compacted with rollers to create a new, stable subbase. The uniformity and the quality of crushing and mixing is affected by the shape and arrangement of the rotor bits, rotational speed, and working speed. Therefore, it is important to understand the behavior of the crushed materials. However, since those actual behaviors inside the rotor hood cannot be observed, an attempt was made to analyze and visualize particle behaviors using the three-dimensional discrete element method (3D-DEM). In this study, an actual stabilizer was used to crush and mix the deteriorated pavement layer in a test section to compare with the analysis results. The surface of the test section was painted with spray paint in six different colors, square grid lines were drawn with white chalk, and a total of 780 numbered stickers were pasted within each grid. After the mixing test, all particles with the numbered stickers were recovered (these particles are called as “marking particles” hereafter), and the moving distance in the front-back direction were measured and a number of particles distributed in the left-right direction was counted. Test results show that about 80% of the crushed marking particles are blown away once and deposited behind the rotor, never to be mixed again. The number of marking particles counted in the left-right direction was similar and uniform. Since the test results were generally similar to the 3D-DEM results, it was concluded that this analytical method is capable of simulating the behavior of crushed material in the rotor hood.

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