An Investigation on the Effects of Aggregates Properties on the Performance of Unbound Aggregate Base Layer

Document Type : Research Paper

Authors

1 Assistant Professor, Department of Civil Engineering, University of Zanjan, Zanjan, Iran

2 MSc. Grad., Department of Civil Engineering, University of Zanjan, Zanjan, Iran

Abstract

Unbound aggregates are the most common type of materials used for construction of the base layer of flexible pavements in Iran and worldwide. Due to the lack of binder, the performance of the compacted unbound aggregates is highly dependent on the properties of the gravel (particles remaining on sieve 4.75mm, sand (particles passing sieve 4.75mm and remaining on sieve 0.75mm), and fines (particles passing sieve No. 200) fraction of the mixture. As the bearing capacity and permeability are the main properties influencing the performance of the base layer; in this research, the effects of the angularity of gravel and sand, and the content and plasticity of fines on the bearing capacity and permeability of the compacted unbound aggregates have been investigated. The bearing capacity of the materials in dry and saturated conditions has been measured using CBR test, and the permeability has been measured using constant head permeability test method. The results showed that the CBR of the compacted mixture decreases with decreasing the percentage of angular sand and gravel in the mixtures. The strength of the mixture was shown to be optimum at a certain amount of fine content and decreases with increasing the plasticity of the fine fraction. It was found that the saturated CBR of the mixtures with non-plastic fines is higher than that of the dry CBR. It was also found that the angularity of the sand is more effective than the angularity of gravel on the CBR. The permeability of the mixtures is shown to increase with decreasing the angularity of the gravel and sand fraction in the mixture.

Keywords

References

-American Association for State Highway and Transportation Officials [AASHTO] (1993) "Guide for design of pavement structures", AASHTO, Washington D.C.
-Barber, J.R. and Ciavarella, M. (2000) "Contact mechanics”, J Solids Struct, Elsevier Sci, 37(1–2): pp. 29–43.
-Bilodeau, J. P. and Dore, G. (2012) "Relating resilient behaviour of compacted unbound base granular materials to matrix and interlock characteristics" Journal of Construction and Building Materials, Vol. 37, pp. 220-228.
-Brown, S. F., Loach, S. C. and OĚ„Reilly, M. P. (1987) "Repeated loading of fine grained soils", TRRL Contractor Report72.
-Carrier III, W. D. (2003) "Goodbye Hazen; Hello Kozeny-Carman", Journal of Geotechnical and Geoenvironmental Eng., Am. Soc. Civ. Eng., vol. 129, no. 11, pp. 1054–1056.
-Cetin, A., Kaya, Z., Cetin, B. and Aydilek, A. H. (2014) "Influence of laboratory compaction method on mechanical and hydraulic characteristics of unbound granular base materials", Journal of Road Materials and Pavement Design, Vol. 15, Number 1, pp. 220- 235.
-Cerni, G, Cardone F, Virgili, A. and Camilli, S. (2012) "Characterization of permanent deformation behaviour of unbound granular materials under repeated triaxial loading" J. Construct Build Mater Elsevier Sci; 28(1):pp. 79–87.
-Chapuis, R. P. (2004) "Predicting the Saturated Hydraulic Conductivity of Sand and Gravel Using Effective Diameter and Void Ratio", Canadian Journal of Geotechnical Engineering, vol. 41, no. 5, pp. 785– 595.
-Das, B. N. (2008) "Advanced soil mechanics-Third Edition", CRC Press, Taylor and Francis, New York, USA.
-Garcia-Rojo, R. and Herrmann, H. (2005) "Shakedown of unbound granular material" Granular Matter, 2005;Vol. 7. Berlin, Heidelberg: Springer; (Issue 2–3, pp. 109–18
-Heukelom, W. and Klomp, A. J. G. (1962) "Dynamic testing as a means of controlling pavements during and after compaction", Proceedings of the First International Conference on Structural Design of Asphalt Pavements, University of Michigan.
-Huang, Y. (2004) "Pavement analysis and design", Prentice Hall, Kentucky.
-Iran Ministry of Roads and Urban Development, Vice Presidency for Strategic Planning and Supervision. Code 234. (2011) "Iranian Asphalt Pavement Code", Tehran.
-Johnson, K. L. (1985) “Contact mechanics", Cambridge University Press, New York, USA.
-Lekarp, F. and Dawson, A. (1998) "Modeling permanent deformation behavior of unbound granular materials" Journal of Construction and Building Materials, 12, pp. 9-18
-Lekarp, F., Isacsson, U. and Dawson, A. (2000) "State of art: resilient response of unbound aggregates", Journal of Transportation Engineering, ASCE, Vol. (1), Jan/Feb.
-Mishra, D. (2012) "Aggregate characteristics affecting response and performance of un-surfaced pavements on weak sub-grades", Ph.D. Dissertation, University of Illinois at Urbana Champaign.
-Nazzal, M., Mohammad, L. and Austin A. (2011) "Evaluation of the shakedown behavior of unbound granular base materials" Geo-Frontiers 2011, American Society of Civil Engineers (ASCE); pp. 4752–4761.
 
-Powell, W. D., Potter, J. F., and Mayhew, H. C. and Numm, M. E. (1984) "The Structural Design of Bituminous Roads", TRRL Report LR 1132.
-Sharp, R. (1985) "Pavement design based on shakedown analysis", Transport Res Record: J. Transport Res Board, Transport Res Board (TRB); 1022: pp. 99–107.
-Soliman, H. and Shalaby, A. (2015) "Permanent deformation behavior of unbound granular base materials with varying moisture and fines content", Journal of Transportation Geotechnics, Vol. 4, pp. 1- 12.
-Tao, M., Mohammad, L., Nazzal, M., Zhang, Z. and Wu, Z. (2010) "Application of shakedown theory in characterizing traditional and recycled pavement base materials", J. Transport Eng Am Soc Civil Eng (ASCE);136(3): pp. 214–22.
-Tuumluer, E. (1995) "Predicting behavior of flexible pavements with granular bases", Ph.D. Dissertation, School of Civil and Environmental Engineering, Georgia, Institute of Technology, Atlanta, GA. 
 
-Werkmeister, S., Dawson, A. and Wellner,,F. (2001) "Permanent deformation behavior of granular materials and the shakedown concept" Transport Res Rec: J Transport Res Board, Transport Res Board (TRB);1757: pp. 75–81.
-Werkmeister, S., Dawson, A. and Wellner, F. (2004) "Pavement design model for unbound granular materials", J. Transport Eng Am Soc Civil Eng (ASCE); 130(5): pp.665–74.
-Werkmeister, S., Dawson, A. and Wellner, F. (2005) "Permanent deformation behavior of granular materials" Road Materials and Pavement Design. Taylor & Francis, 6(1), pp. 31–51.
-Xiao, Y., Tutumluer, E. and Siekmeier, J. (2011) "Mechanistic empirical evaluation of aggregate base/granular subbase quality affecting flexible pavement performance in Minnesota", 90th Annual Meeting of the Transportation Research Board, January 2011, Washington, DC., US
International Journal of Transportation Engineering
Volume 3, Issue 2 - Serial Number 2
October 2015
Pages 151-164

Files

Share

How to cite

Statistics