Commenced in January 2007
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Laboratory Investigation of the Pavement Condition in Lebanon: Implementation of Reclaimed Asphalt Pavement in the Base Course and Asphalt Layer

Authors: Marinelle El-Khoury, Lina Bouhaya, Nivine Abbas, Hassan Sleiman


The road network in the north of Lebanon is a prime example of the lack of pavement design and execution in Lebanon.  These roads show major distresses and hence, should be tested and evaluated. The aim of this research is to investigate and determine the deficiencies in road surface design in Lebanon, and to propose an environmentally friendly asphalt mix design. This paper consists of several parts: (i) evaluating pavement performance and structural behavior, (ii) identifying the distresses using visual examination followed by laboratory tests, (iii) deciding the optimal solution where rehabilitation or reconstruction is required and finally, (iv) identifying a sustainable method, which uses recycled material in the proposed mix. The asphalt formula contains Reclaimed Asphalt Pavement (RAP) in the base course layer and in the asphalt layer. Visual inspection of the roads in Tripoli shows that these roads face a high level of distress severity. Consequently, the pavement should be reconstructed rather than simply rehabilitated. Coring was done to determine the pavement layer thickness. The results were compared to the American Association of State Highway and Transportation Officials (AASHTO) design methodology and showed that the existing asphalt thickness is lower than the required asphalt thickness. Prior to the pavement reconstruction, the road materials were tested according to the American Society for Testing and Materials (ASTM) specification to identify whether the materials are suitable. Accordingly, the ASTM tests that were performed on the base course are Sieve analysis, Atterberg limits, modified proctor, Los Angeles, and California Bearing Ratio (CBR) tests. Results show a CBR value higher than 70%. Hence, these aggregates could be used as a base course layer. The asphalt layer was also tested and the results of the Marshall flow and stability tests meet the ASTM specifications. In the last section, an environmentally friendly mix was proposed. An optimal RAP percentage of 30%, which produced a well graded base course and asphalt mix, was determined through a series of trials.

Keywords: Asphalt mix, reclaimed asphalt pavement, California bearing ratio, sustainability.

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[1] J. S. M. and W. Y. Bellinger, “Distress Identification Manual for the Long-Term Pavement Performance Program (Fifth Revised Edition),” 2014.
[2] ASTM D 6433, “Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys,” 2010.
[3] H. Bjurström, A. Gudmarsson, N. Ryden, and J. Starkhammar, “Field and laboratory stress-wave measurements of asphalt concrete,” Constr. Build. Mater., vol. 126, pp. 508–516, 2016.
[4] K. Jain, S. S. Jain, and M. S. Chauhan, “Selection of Optimum Maintenance and Rehabilitation Strategy for multilane highways,” Int. J. Traffic Transp. Eng., vol. 3, no. 3, pp. 269–278, 2013.
[5] K. A. Abaza, “Performance-Based Models for Flexible Pavement Structural Overlay Design,” J. Transp. Eng., vol. 131, no. February, pp. 149–159, 2005.
[6] A. Bianchini, C. R. Gonzalez, and H. P. Bell, “Correction for the asphalt overlay thickness of flexible pavements considering pavement conditions,” Int. J. Pavement Eng., vol. 8436, p. 0, 2016.
[7] Asphalt institute method, “Strengthening Existing Pavements,” in Asphalt institute method, .
[8] AASHTO, AASHTO Guide for Design of Pavement Structures. American Association of State Highway and Transportation Officials, 1993.
[9] D. C. Saha and J. N. Mandal, “Laboratory Investigations on Reclaimed Asphalt Pavement (RAP) for using it as Base Course of Flexible Pavement,” Procedia Eng., vol. 189, no. May, pp. 434–439, 2017.
[10] L. Noferini, A. Simone, C. Sangiorgi, and F. Mazzotta, “Investigation on performances of asphalt mixtures made with Reclaimed Asphalt Pavement: Effects of interaction between virgin and RAP bitumen,” Int. J. Pavement Res. Technol., vol. 10, no. 4, pp. 322–332, 2017.
[11] ASTM D 3459, “Standard Test Method for Humid-Dry Cycling for Coatings on Wood and Wood Products,” in Annual Book of ASTM Standards, 1998, pp. 5–6.
[12] ASTM D 422, “Standard Test Method for Particle-Size Analysis of Soils,” in Annual Book of ASTM Standards, 2007, pp. 1–8.
[13] ASTM D 1140, “Standard Test Methods for Amount of Material in Soils Finer than No. 200 (75-µm) Sieve,” in Annual Book of ASTM Standards, 2006, pp. 1–4.
[14] ASTM D 3515, “Standard Specification for Hot-Mixed, Hot-Laid Bituminous Paving Mixtures,” in Annual Book of American Society for Testing materiasl ASTM Standards, vol. 04, 1996, pp. 1–5.
[15] ASTM D 4318, “Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils,” in Annual Book of ASTM Standards, 2010, pp. 1–16.
[16] ASTM C 535, “Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine 1,” in Annual Book of ASTM Standards, 2009, pp. 49–51.
[17] ASTM D 1557, “Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,700 kN-m/m3)),” in Annual Book of ASTM Standards, 2009, pp. 1–14.
[18] ASTM D 1883, “Standard Test Method for CBR (California Bearing Ratio) of Laboratory-Compacted Soils,” in Annual Book of ASTM Standards, 2010, pp. 1–9.
[19] ASTM D 6927, “Standard Test Method for Marshall Stability and Flow of Bituminous Mixtures,” in Annual Book of ASTM Standards, 2006.