Investigating the Sensitivity of Aggregate Size within Sand Mastic by Modeling the Microstructure of an Asphalt Mixture
Publication: Journal of Materials in Civil Engineering
Volume 23, Issue 5
Abstract
The objective of this study is to investigate the sensitivity of aggregate size within sand mastic by modeling the microstructure of an asphalt mixture. The sensitivity of the maximum aggregate size on the sand mastic phase is investigated through discrete-element simulations. A three-dimensional (3D) discrete-element model of asphalt mixture was prepared from X-ray computed tomography (X-ray CT) images. In the discrete-element model, an asphalt mixture is divided into aggregate, sand mastic, and air void phases. In this study, the sand mastic is defined as fines and fine aggregates mixed with asphalt binder. Three different nominal maximum aggregate sizes (NMASs) of sand mastic, namely, 1.18 mm, 0.6 mm, and 0.3 mm, were used in the 3D model to investigate the best gradation of sand mastic. The dynamic moduli of three different NMASs of sand mastic were measured for use in the 3D discrete-element modeling simulation. Laboratory-measured dynamic moduli of asphalt mixtures were compared with prediction results. The sand mastics with NMASs of 1.18 mm and 0.6 mm could be used to predict the asphalt mixture modulus across a range of temperatures and loading frequencies with good accuracy. The sand mastic with a NMAS of 0.3 mm overpredicted at high and low temperatures. The overprediction resulted from the difficulty of proper visualization of the smaller aggregate size in the model.
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Acknowledgments
This material is based in part upon work supported by the National Science Foundation under Grant NSF0701264. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. This research could not have been completed without the significant contributions of Drs. M. Emin Kutay, Qingli Dai, and Thomas Van Dam.
References
Abbas, A., Masad, E., Papagiannakis, T., and Shenoy, A. (2005). “Modelling asphalt mastic stiffness using discrete element analysis and micromechanics-based models.” Int. J. Pavement Eng., 6(2), 137–146.
Buttlar, W. G., Bozkurt, D., Al-Khateeb, G. G., and Waldhoff, A. S. (1999). “Understanding asphalt mastic behavior through micromechanics.” Transportation Research Record 1681, Transportation Research Board, Washington, DC, 157–169.
Buttlar, W. G., and You, Z. (2001). “Discrete element modeling of asphalt concrete: Microfabric approach.” Transportation Research Record, 1757, Transportation Research Board, Washington, DC, 111–118.
Cundall, P. A. (1971). “A computer model for simulating progressive large scale movements in blocky rock systems.” Proc. of the Symp. of the Int. Soc. of Rock Mechanics, Nancy, France, II-8.
Cundall, P. A. (1987). “Distinct element models of rock and soil structure.” Analytical and computational methods in engineering rock mechanics, E. T. Brown, ed., George Allen and Unwin, London, 129–163.
Cundall, P. A. (1990). “Numerical modelling of jointed and faulted rock.” Proc. of the Int. Conf. on Mechanics of Jointed and Faulted Rock, 11.
Cundall, P. A. (2000). “A discontinuous future for numerical modelling in geomechanics.” Geotech. Geol. Eng., 149(1), 41–47.
Itasca Consulting Group. (2008). “PFC 3D Version 4.0.” Minneapolis.
Lee, X., and Dass, W. C. (1993). Experimental study of granular packing structure changes under load, Elsevier Science, Birmingham, UK, 17.
Masad, E. (2004). “X-ray computed tomography of aggregates and asphalt mixes.” Materials Evaluation, 62(7), 775–783.
Masad, E., Muhunthan, B., Shashidhar, N., and Harman, T. (1999). “Quantifying laboratory compaction effects on the internal structure of asphalt concrete.” Transportation Research Record 1681, Transportation Research Board, Washington, DC, 179–185.
Shashidhar, N. (1999). “X-ray tomography of asphalt concrete.” Transportation Research Record 1681, Transportation Research Board, Washington, DC, 186–192.
Synolakis, C. E., Zhou, Z., and Leahy, R. M. (1996). “Determination of internal deformation field in asphalt cores using x-ray computer tomography.” Transportation Research Record 1526, Transportation Research Board, Washington, DC, 135–141.
Thornton, C. (1979). “Conditions for failure of a face-centered cubic array of uniform rigid spheres.” Geotechnique, 29(4), 441–459.
Wang, L. B., Frost, J. D., and Lai, J. S. (2004). “Three-dimensional digital representation of granular material microstructure from X-ray tomography imaging.” J. Comput. Civ. Eng., 18(1), 28–35.
Wang, Y., Wang, L. B., and Harman, T. P. (2007). “Noninvasive measurement of three-dimensional permanent strains in asphalt concrete with X-ray tomography imaging.” Transportation Research Record 2005, Transportation Research Board, Washington, DC, 95–103.
You, Z., Adhikari, S., and Dai, Q. (2008a). “Three-dimensional discrete element models for asphalt mixtures.” J. Eng. Mech., 134(12), 1053–1063.
You, Z., Adhikari, S., and Kutay, M. E. (2008b). “Dynamic modulus simulation of the asphalt concrete using the X-ray computed tomography images.” Mater. Struct., 42, (5), 617–630.
You, Z., and Buttlar, W. G. (2006). “Micromechanical modeling approach to predict compressive dynamic moduli of asphalt mixture using the distinct element method.” Transportation Research Record, Transportation Research Board, Washington, DC, 73–83.
You, Z., and Dai, Q. (2007a). “Dynamic complex modulus predictions of hot-mix asphalt using a micromechanical-based finite element mode.” Can. J. Civ. Eng., 34(12), 1519–1528.
You, Z., and Dai, Q. (2007b). “A review of advances in micromechanical modeling of aggregate-aggregate interaction in asphalt mixture.” Can. J. Civ. Eng., 34(2), 239–252.
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© 2011 American Society of Civil Engineers.
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Received: Oct 27, 2008
Accepted: Oct 22, 2010
Published online: Oct 27, 2010
Published in print: May 1, 2011
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