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

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service life and performance of paved as well as unpaved roads and reduce the required thickness of the base course (Giroud and Han 2004). Common geosynthetics used in roadway construction are geotextile, geomembrane, geogrid, geocell, geonet, geofoam, geocomposite, etc. The major functions of geosynthetics include separation, filtration, drainage, reinforcement, protection, and/or barrier, etc. The use of 100% RAP as a base material reinforced by geocell is a new concept developed by Han et al. (2011) and Thakur (2011). The use of RAP is a sustainable approach for constructing new roads and rehabilitating existing roads. The use of geocell improves the mechanical properties of RAP, thereby improving the performance of RAP bases and pavements. Due to the three-dimensional configuration of geocell, it can provide better lateral and vertical confinement, distribute the load over a wider area, increase the bearing capacity, and reduce settlement or rutting. Moreover, a geocell-reinforced pavement system is a composite structure and it has benefits from combined advantages. 1.2 Problem Statement Asphalt pavements deteriorate with traffic (especially heavy trucks) and time. Maintenance and overlaying may solve minor to medium pavement distress problems. When the condition of a pavement becomes badly deteriorated, reconstruction of the pavement may become an economic and feasible solution. Reconstruction of a pavement requires removal of pavement surfaces. For the most part, the removed pavement surfaces are transported to a plant for processing into recycled asphalt pavement (RAP) materials. The RAP materials are then re- mixed with virgin binder and aggregate to produce hot mix asphalt (HMA) or they are used as base courses. Obviously, the transportation and processes of RAP consume energy and increase cost. 2
On-site use of RAP materials has recognizable economic, environmental, and sustainability benefits. One attractive option is to use RAP materials as base courses onsite with a thin new overlay. However, RAP is characterized as a time, temperature, and stress-dependent material, which means it creeps under a sustained load due to the presence of asphalt binder. According to Bartenov and Zuyev (1999), static fatigue and dynamic fatigue are two interrelated thermally activated processes pertaining to a viscoelastic material like RAP. The material, subjected to static fatigue, is regarded as one subjected to creep. Cosentino et al. (2003) and Viyanant et al. (2007) both confirmed that fully confined and triaxially confined RAP samples creep under static loading. The creep test is shown to be sensitive to mixture variables including asphalt grade, binder content, aggregate type, air void content, testing temperature, and testing stress. The previous study by Thakur et al. (2011) showed that the use of geocell to confine RAP could minimize creep of RAP under a sustained load. However, the performance of geocell- reinforced RAP as a base course overlaid by an asphalt surface is unknown. 1.3 Research Objective The objective of the current research is to evaluate the behavior and performance of the geocell-reinforced RAP bases in a flexible pavement under cyclic loading. This study simulated onsite use of RAP with geocells to reconstruct damaged pavements under heavy trucks. The test data obtained from this research would provide the basis for the development of a new design procedure for geocell-reinforced flexible pavements with RAP base courses. 1.4 Research Methodology The research methodology adopted for this research work includes an extensive literature review on geosynthetics (especially geocells), RAP, and geocell-reinforced granular bases, experimental tests on unreinforced and geocell-reinforced flexible pavements with RAP bases, 3
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 and 16: Abstract Asphalt pavements deterior
Page 17: 1.1 Background Chapter 1 Introducti
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
Page 69 and 70:
dynamic deformation moduli from LWD
Page 71 and 72:
Depth (cm.) 0.00 5.00 10.00 15.00 2
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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
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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 93 and 94:
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
Page 111 and 112:
Figures 4.58 and 4.59 show the meas
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Strain (%) 0.04 0.02 0 -0.02 -0.04
Page 115 and 116:
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
Page 121 and 122:
Table 4.10 Number of loading cycles
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Table 4.11 Elastic deformation and
Page 125 and 126:
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
Page 137:
Pokharel, S. K., J. Han, D. Leshchi
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