Onsite Use of Recycled Asphalt Pavement Materials and Geocells to ...

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subgrade and base to measure the vertical stresses applied on the subgrade. Tell tales were placed at the interface of subgrade and base and the interface of base and HMA surface to measure their corresponding compression. Strain gauges were placed on geocells and at the bottom of the HMA layer to measure the strains. Large-scale plate load tests with a cyclic load up to 40 kN was applied to simulate heavy truck wheel loading until permanent deformation exceeding the failure criterion of 25 mm. Six cyclic plate load tests were conducted on unreinforced and geocell-reinforced test sections by varying the thickness of the RAP base. The performance of each test section under cyclic loading was evaluated for a number of loading cycles up to the failure of the test section. The test results show better performance of the geocell-reinforced section than the unreinforced section at the same base thickness. The higher stress distribution angle, higher percentage of elastic deformation, lower compression of HMA surface, and lower compression of RAP base were observed in the geocell-reinforced test section as compared with those in the unreinforced test section. The compression of subgrade was high compared to that of RAP base and HMA layers. The geocell-reinforced section with higher stiffness resulted in better compaction of the HMA layer as evidenced with lower air voids as well. The subgrade and/or RAP base layer with a higher CBR value improved the performance of the pavement section. To obtain consistent test results, it is important to follow the same procedure to prepare and test the pavement section. xv
1.1 Background Chapter 1 Introduction The United States has one of the largest road systems in the world. According to the National Asphalt Pavement Association (NAPA), more than 90% of U.S. roads are paved with hot mix asphalt (HMA) on the surface layer (FHWA-HRT-10-001, 2010). Factors such as aged roads, rapid growth in traffic volume, and high axle loads necessitate the maintenance and rehabilitation of existing roads, as well as the construction of new roads. In turn, demand for a large quantity of construction materials derived from natural resources, such as aggregate and asphalt binder, is high. The escalating cost and scarcity of these materials, and their transportation to a desired construction site, require transportation agencies to explore new and sustainable alternatives of constructing and maintaining roads. Recycling of waste materials can be one such alternative. Old-aged HMA pavement material is the most recyclable material obtained from roads near or past their design life. Reprocessed HMA waste is also called “Recycled Asphalt Pavement” (RAP). The use of RAP has several benefits, such as the preservation of natural resources for future generations, protection of the environment, and the conservation of energy. Therefore, the use of RAP is a sustainable approach. RAP has been used mostly in new HMA mix for pavement surfaces; however, it has been increasingly used as a base course material for construction of new roads or rehabilitation of existing roads. Geosynthetic materials have been used in road construction to stabilize soft soil all over the world. The concept of stabilizing a road using natural materials as reinforcement dates back to 3000 BC (Kerisel 1985). One of the earliest uses of geosynthetics for roadway construction occurred in 1920s (Becham et al. 1935). A review of the literature shows that the inclusion of geosynthetics at the subgrade-base interface, or even within the base course, can improve the 1
Page 1 and 2: Report # MATC-KU: 462 Final Report
Page 3 and 4: Technical Report Documentation Page
Page 5 and 6: 4.3.4 15 cm Thick Geocell-Reinforce
Page 7 and 8: Figure 4.11 Profiles of the HMA sur
Page 9 and 10: Figure 4.48 The permanent deformati
Page 11 and 12: List of Tables Table 2.1 Percentage
Page 13 and 14: Acknowledgements This research was
Page 15: Abstract Asphalt pavements deterior
Page 19 and 20: On-site use of RAP materials has re
Page 21 and 22: Chapter 2 Literature Review Recycle
Page 23 and 24: Protection. Geosynthetics are somet
Page 25 and 26: wet weather conditions. Webster and
Page 27 and 28: subgrade can be improved in terms o
Page 29 and 30: annually in the early 1990s (FHWA-H
Page 31 and 32: Figure 2.2 Usage and potential of v
Page 33 and 34: Table 2.1 Percentage of use of RAP
Page 35 and 36: Type of Property Physical Propertie
Page 37 and 38: permeability values. The addition o
Page 39 and 40: Chapter 3 Material Properties and E
Page 41 and 42: Table 3.1 Properties of the RAP bas
Page 43 and 44: 3.3 Asphalt Concrete Figure 3.4 Sta
Page 45 and 46: Table 3.2 Basic Properties of NPA g
Page 47 and 48: Earth pressure cells were installed
Page 49 and 50: central pocket, and one at the top
Page 51 and 52: plate on one end was buried at the
Page 53 and 54: loading plate to simulate the rubbe
Page 55 and 56: 3.6.7 Dynamic Cone Penetration Test
Page 57 and 58: Figure 3.15 Light weight deflectome
Page 59 and 60: Chapter 4 Experimental Data Analysi
Page 61 and 62: The quantity of RAP placed in each
Page 63 and 64: Geocell infilled with RAP Geocell i
Page 65 and 66: Figure 4.4 Prime coat on the RAP ba
Page 67 and 68:
4.2 Cyclic Plate Load Tests Figure
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dynamic deformation moduli from LWD
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Depth (cm.) 0.00 5.00 10.00 15.00 2
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Depth (cm.) 10 14 18 22 26 Before t
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surface at the center was under ten
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4.3.3 15 cm Thick Geocell-Reinforce
Page 79 and 80:
Depth (cm.) 0 10 20 30 40 50 60 0 5
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The permanent deformation was obtai
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Strain on geocell (%) Figure 4.23 T
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Stress distribution angle (°) 50 4
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Figure 4.28 The calculated dynamic
Page 89 and 90:
Elastic deformation (mm.) 3 2.5 2 1
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Strain (%) 0.15 0.1 0.05 0 -0.05 -0
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Page 95 and 96:
The profiles of the HMA surfaces as
Page 97 and 98:
Figure 4.41 shows the measured maxi
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Figure 4.43 The vertical stress at
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Table 4.5 The average CBR values of
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at the distances of 25 and 50 cm aw
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Strain (%) 0.014 0.012 0.01 0.008 0
Page 107 and 108:
Page 109 and 110:
The profiles of the HMA surfaces as
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Figures 4.58 and 4.59 show the meas
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Strain (%) 0.04 0.02 0 -0.02 -0.04
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4.4 Analysis of Test Data Six cycli
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Table 4.7 Average CBR values of tes
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The percentages of air void of the
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Table 4.10 Number of loading cycles
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Table 4.11 Elastic deformation and
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HMA surface compression (mm.) Base
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strain was higher for the geocell a
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Vertical stress (kPa) 250 200 150 1
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Stress distribution angle ( ̊) 80
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6. The subgrade contributed to most
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Berthelot, C., R. Haichert, D. Podb
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Pokharel, S. K., J. Han, D. Leshchi
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