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

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The Evd values of the subgrade and the base increased with an increase of the size of the loading plate for most of the tests. However, the Evd values of the HMA surface were the highest in most of the test sections when the 20 cm loading plate was used. The Evd values decreased from the HMA surface, the RAP base to the subgrade in all the test sections. 4.4.3 Percent of Air Void in the HMA Surface Percent of air void (Va) is an important physical property of compacted dense or open HMA which is used to correlate with its performance. This parameter affects the overall stability and durability of the pavement. Lower percent of air void in the mixture can cause excessive rutting of the pavement due to plastic flow. However, higher percent of air void provides more permeable surface to the air and water, which can result in a higher rate of oxidation of asphalt binder and ultimately premature cracking or raveling of the HMA surface. The bulk specific gravity (GBS) and the theoretical maximum specific gravity (GMS) of the HMA samples obtained by the core cutter were determined in the laboratory and are provided in table 4.9. The percentages of air void of the samples were then calculated using Eq. (3.3) and are presented in table 4.9. Base Thickness (cm) Reinforcement Unreinforced Bulk Specific Gravity Maximum Theoretical Specific Gravity Percent of Air Void (%) Table 4.9 Percent of air void of the HMA sample 15 15 15 23 30 30 Reinforced (hard subgrade) Reinforced Reinforced Unreinforced Reinforced 2.09 2.18 2.08 2.14 2.15 2.16 2.26 2.33 2.23 2.31 2.31 2.30 7.64 6.59 6.81 7.01 7.18 6.08 102
The percentages of air void of the HMA samples ranged from 6.08 to 7.64 %, which show relatively consistent density of the HMA surfaces in all the test sections. It is shown that the test section with hard subgrade and base had the lower percent of air void. The reinforced test sections had lower percentages of air void than the unreinforced test sections. These results indicate that hard subgrade and/or base courses (including geocell-reinforced bases) helped the compaction of the HMA and resulted in denser HMA surfaces. 4.4.4 Permanent Deformation on the HMA Surface Figure 4.64 shows the permanent deformations on the HMA surface at the center versus the number of loading cycles for all six test sections. It is shown that the permanent deformation increased at a higher rate at the beginning and then increased at a reduced rate after a certain number of loading cycles. The unreinforced base sections had higher rates of the increase in the permanent deformations than the geocell-reinforced sections. The thinner base sections had higher rates of the increase in the permanent deformations than the thicker base sections. In addition, the test section with hard subgrade and base course had a lower rate of the increase in the permanent deformations. Figure 4.64 also shows that the 15 cm thick geocell-reinforced base section had an equivalent or even better performance than the 30 cm thick unreinforced base section. The surface permanent deformation of 25 mm is often used as a criterion for a tolerable deformation of a pavement. The number of loading cycles at the 25 mm permanent deformation in each test is presented in table 4.10. It is shown that the 15 cm thick reinforced base section with hard subgrade and base and the 30 cm thick geocell-reinforced base section had the largest number of load cycles. The 15 cm thick unreinforced base section had the smallest number of load cycles. The improvement of the pavement performance can be defined as the traffic benefit 103
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Report # MATC-KU: 462 Final Report
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Technical Report Documentation Page
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4.3.4 15 cm Thick Geocell-Reinforce
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Figure 4.11 Profiles of the HMA sur
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Figure 4.48 The permanent deformati
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List of Tables Table 2.1 Percentage
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Acknowledgements This research was
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Abstract Asphalt pavements deterior
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1.1 Background Chapter 1 Introducti
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On-site use of RAP materials has re
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Chapter 2 Literature Review Recycle
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Protection. Geosynthetics are somet
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wet weather conditions. Webster and
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subgrade can be improved in terms o
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annually in the early 1990s (FHWA-H
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Figure 2.2 Usage and potential of v
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Table 2.1 Percentage of use of RAP
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Type of Property Physical Propertie
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permeability values. The addition o
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Chapter 3 Material Properties and E
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Table 3.1 Properties of the RAP bas
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3.3 Asphalt Concrete Figure 3.4 Sta
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Table 3.2 Basic Properties of NPA g
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Earth pressure cells were installed
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central pocket, and one at the top
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plate on one end was buried at the
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loading plate to simulate the rubbe
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3.6.7 Dynamic Cone Penetration Test
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Figure 3.15 Light weight deflectome
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Chapter 4 Experimental Data Analysi
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The quantity of RAP placed in each
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Geocell infilled with RAP Geocell i
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Figure 4.4 Prime coat on the RAP ba
Page 67 and 68: 4.2 Cyclic Plate Load Tests Figure
Page 69 and 70: dynamic deformation moduli from LWD
Page 71 and 72: Depth (cm.) 0.00 5.00 10.00 15.00 2
Page 73 and 74: Depth (cm.) 10 14 18 22 26 Before t
Page 75 and 76: surface at the center was under ten
Page 77 and 78: 4.3.3 15 cm Thick Geocell-Reinforce
Page 79 and 80: Depth (cm.) 0 10 20 30 40 50 60 0 5
Page 81 and 82: The permanent deformation was obtai
Page 83 and 84: Strain on geocell (%) Figure 4.23 T
Page 85 and 86: Stress distribution angle (°) 50 4
Page 87 and 88: Figure 4.28 The calculated dynamic
Page 89 and 90: Elastic deformation (mm.) 3 2.5 2 1
Page 91 and 92: Strain (%) 0.15 0.1 0.05 0 -0.05 -0
Page 95 and 96: The profiles of the HMA surfaces as
Page 97 and 98: Figure 4.41 shows the measured maxi
Page 99 and 100: Figure 4.43 The vertical stress at
Page 101 and 102: Table 4.5 The average CBR values of
Page 103 and 104: at the distances of 25 and 50 cm aw
Page 105 and 106: Strain (%) 0.014 0.012 0.01 0.008 0
Page 109 and 110: The profiles of the HMA surfaces as
Page 111 and 112: Figures 4.58 and 4.59 show the meas
Page 113 and 114: Strain (%) 0.04 0.02 0 -0.02 -0.04
Page 115 and 116: 4.4 Analysis of Test Data Six cycli
Page 117: Table 4.7 Average CBR values of tes
Page 121 and 122: Table 4.10 Number of loading cycles
Page 123 and 124: Table 4.11 Elastic deformation and
Page 125 and 126: HMA surface compression (mm.) Base
Page 127 and 128: strain was higher for the geocell a
Page 129 and 130: Vertical stress (kPa) 250 200 150 1
Page 131 and 132: Stress distribution angle ( ̊) 80
Page 133 and 134: 6. The subgrade contributed to most
Page 135 and 136: Berthelot, C., R. Haichert, D. Podb
Page 137: Pokharel, S. K., J. Han, D. Leshchi
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Onsite Use of Recycled Asphalt Pavement Materials and Geocells to ...

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