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

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RAP blended samples decreased as the percentage of RAP was increased. Results from Proctor compaction tests indicated that the maximum dry unit weight and optimum water content decreased with the addition of RAP. Shear strength tests showed that blending of RAP with aggregate resulted in a more ductile and softer response than that of the virgin (unblended) aggregate. The secant modulus of the blend at low strain decreased as the percentage of RAP in the sample was increased. As the RAP content increased, the stiffness of the blend decreased and approached that of the blend with 75% RAP content. The large direct shear tests showed that the shear strength of the blend decreased up to 20% with the increase of RAP, and appeared to level off with no significant change as the RAP content was increased to 75%. Constant head permeability tests indicated that the permeability of the blend increased as the percentage of RAP increased. The addition of RAP to the crushed angular aggregate had a minor effect on the R- value, while the addition of RAP to the natural pit run soil resulted in an increase of the R-value. Mokwa and Peebles (2005) concluded that the R-value was primarily dependent upon the properties of the virgin aggregate, and was only secondarily influenced by the percentage of RAP. In contrast, Bennert and Maher (2005) found that as the percentage of RAP in the blend of base courses increased, both the CBR and permeability values decreased, but permanent deformation increased. To evaluate the potential use of RAP and recycled concrete aggregate (RCA) as base and sub-base materials, the New Jersey Department of Transportation conducted the following performance tests: permeability (falling head and constant head tests), triaxial shear strength, cyclic triaxial loading, California Bearing Ratio (CBR), and resilient modulus tests. The test results showed that an increase of the percent of RAP in the blend reduced both the CBR and 20
permeability values. The addition of RAP also caused larger permanent deformations during cyclic triaxial testing. Mechanistic-Empirical Pavement Design Guide (MEPDG) requires resilient moduli of unbound layers for pavement design. The laboratory tests showed that as RAP content was increased, the resilient modulus of the blend increased (Alam et al. 2009). RAP has a potential to be used in high percentages as pavement bases, which may help alleviate a growing environmental problem while providing a strong pavement foundation. Kim et al. (2007) carried out resilient modulus tests on specimens with different ratios of RAP to aggregate. The test results show that specimens at 65% optimum moisture content (OMC) were stiffer than specimens at 100% OMC at all confining pressures. The 50% aggregate-50% RAP specimens had stiffness equivalent to 100% aggregate specimens at lower confining pressures. At higher confining pressures, the blended RAP specimens were even stiffer. However, the test results indicated that specimens with RAP exhibited larger permanent deformation than those with 100% aggregate. The effect of moisture content on the resilient modulus of RAP base layer was similar to its effect on virgin aggregate base course. The resilient modulus of the RAP base layer decreased with an increase in moisture content (Mohamed et al. 2010). 2.3 Summary of Past Studies Findings from previous studies on geosynthetics and RAP are summarized as follows: i. The inclusion of geosynthetics in pavements reduces required base thickness, increases bearing capacity, and increases pavement life. 21
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 and 18: 1.1 Background Chapter 1 Introducti
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: Type of Property Physical Propertie
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
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 93 and 94:
4.3.5 23 cm Thick Geocell-Reinforce
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 107 and 108:
4.3.7 30 cm Thick Geocell-Reinforce
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 and 118:
Table 4.7 Average CBR values of tes
Page 119 and 120:
The percentages of air void of the
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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