Study of Compaction in Hot-Mix Asphalt Using Computer Simulations

Authors: Kasthurirangan Gopalakrishnan, Naga Shashidhar, Xiaoxiong Zhong

Abstract:

During the process of compaction in Hot-Mix Asphalt (HMA) mixtures, the distance between aggregate particles decreases as they come together and eliminate air-voids. By measuring the inter-particle distances in a cut-section of a HMA sample the degree of compaction can be estimated. For this, a calibration curve is generated by computer simulation technique when the gradation and asphalt content of the HMA mixture are known. A two-dimensional cross section of HMA specimen was simulated using the mixture design information (gradation, asphalt content and air-void content). Nearest neighbor distance methods such as Delaunay triangulation were used to study the changes in inter-particle distance and area distribution during the process of compaction in HMA. Such computer simulations would enable making several hundreds of repetitions in a short period of time without the necessity to compact and analyze laboratory specimens in order to obtain good statistics on the parameters defined. The distributions for the statistical parameters based on computer simulations showed similar trends as those of laboratory specimens.

Keywords: Computer simulations, Hot-Mix Asphalt (HMA), inter-particle distance, image analysis, nearest neighbor

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1081830

References:

[1] Z. Q. Yue and I. Morin, "Digital image processing for aggregate orientation in asphalt concrete mixtures," Canadian Journal of Civil Engineering, vol. 23, 1996, pp. 480-489.
[2] E. Masad and J. Button, "Implications of experimental measurements and analyses of the internal structure of hot-mix asphalt," Transportation Research Record no. 1891, TRB, 2004, pp. 212-220.
[3] Z. Q. Yue., W. Bekking, and I. Morin, "Application of digital image processing to quantitative study of asphalt concrete microstructure." Transportation Research Record no. 1492, TRB, 1995, pp. 53-60.
[4] E. Masad, B. Muhunthan, N. Shashidhar, and T. Harman, "Quantifying laboratory compaction effects on the internal structure of asphalt concrete," Transportation Research Record no. 1681, TRB, 1999, pp. 179-185.
[5] E. Masad, B. Muhunthan, N. Shashidhar, and T. Harman, "Internal structure characterization of asphalt concrete using image analysis," Journal of Computing in Civil Engineering, ASCE, vol. 13, no. 2, 1999, pp. 88-95.
[6] L. Tashman, E. Masad, B. Peterson, and H. Saleh, "Internal structure analysis of asphalt mixes to improve the simulation of Superpave gyratory compaction to field conditions," Journal of the Association of Asphalt Paving Technologists, vol. 70, 2001, pp. 605-645.
[7] S. Saadeh, L. Tashman, E. Masad, and W. Mogawer, "Spatial and directional distributions of aggregates in asphalt mixes," Journal of Testing and Evaluation, ASTM, vol. 30, no. 6, 2002, pp. 483-491.
[8] L. B. Wang, H. S. Paul, T. Harman, and J. D. Angelo, "Characterization of aggregates and asphalt concrete using X-ray computerized tomography: A state-of-the-art report," Journal of the Association of Asphalt Paving Technologists, vol. 73, 2004, pp. 467-500.
[9] K. Gopalakrishnan, H. Ceylan, F. Inanc, J. Gray, and M. Heitzman, "Characterization of asphalt materials using X-ray high-resolution computed tomography imaging techniques," in Proc. (in press), 2006 T&DI Airfield and Highway Pavement Specialty Conference, Atlanta, Georgia, 2006.
[10] A. E. Hunter, G. D. Airey, and A. C. Collop, "Aggregate orientation and segregation in laboratory-compacted asphalt samples," Transportation Research Record no. 1891, TRB, 2004, pp. 8-15.
[11] K. Gopalakrishnan, N. Shashidhar, and X. Zhong, "Attempt at quantifying the degree of compaction in HMA using image analysis," ASCE Geotechnical Special Publication no. 130, 2005, pp. 225-239.
[12] E. J. Garboczi, and D. P. Bentz, "Computer simulation of the diffusivity of cement-based materials," Journal of Materials Science, vol. 27, 1992, pp. 2083-2092.
[13] Z. You and W. G. Buttlar, "Development of a microfabric discrete element modeling techniques to predict complex modulus of asphaltaggregate hollow cylinders subjected to internal pressure," in Proc., 84th Annual Meeting of the Transportation Research Board, Washington, D.C., 2005.
[14] N. Shashidhar and K. Gopalakrishnan, "Evaluating the aggregate structure in hot-mix asphalt using three-dimensional computer modeling and particle packing simulations," Accepted for publication in the Canadian Journal of Civil Engineering.
[15] J. R. Shewchuk, "Triangle: engineering a 2D quality mesh generator and DeLaunay triangulator," in Proc., First Workshop on Applied Computational Geometry, 1996, pp. 124-133.
[16] L. J. Guibas and J. Stolfi, "Primitives for the manipulations of general subdivisions and the computation of Voronoi diagrams," ACM Trans. on Graphics, vol. 4, 1985, pp. 74-123.