October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 1/43 UW – Madison Geological Engineering Geological Engineering Transportation Geotechnics Civil & Environmental Engineering Behavior of Recycled Asphalt Pavement and Recycled Concrete Aggregate as Unbound Road Base James M. Tinjum, PhD, PE Assistant Professor Geological Engineering
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Behavior of Recycled Asphalt Pavement and Recycled ...s/Tinjum.pdfOctober 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 2/43 Objective
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October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 1/43
Effect of RAP or RCA Content on Stiffness of Natural Aggregate
Blends
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 34/43
Materials Selected for Blends
RAP RCA Natural Aggregate
California Minnesota
Minnesota
(Class 5) Colorado
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 35/43
PSD of RAPs and Class 5 Used in Blends
0
10
20
30
40
50
60
70
80
90
100
0.010.1110100
Pe
rce
nt F
ine
r (%
)
Particle Size (mm)
Class 5 (MN)
RAP (CA)
RAP (CO)
RAP Lower Bound
(Literature) RAP Upper Bound
(Literature)
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 36/43
PSD of RCA (MN) and Class 5 Used in Blends
0
10
20
30
40
50
60
70
80
90
100
0.010.1110100
Particle Size (mm)
Class 5 (MN)
RCA (MN)
RCA Lower Bound
(Literature)
RCA Upper Bound
(Literature)
Pe
rce
nt
Fin
er
(%)
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 37/43
Compaction Curves: RAP (CA) and RAP (CO) Blends
19
20
21
22
0 2 4 6 8 10 12
Dry
Weig
ht,
(kN
/m3)
Water Content (%)
Class 5 (MN)
Blend (50-50)
RAP (CA)
19
20
21
22
0 2 4 6 8 10 12
Dry
Weig
ht, (
kN
/m3)
Water Content (%)
Class 5 (MN)
Blend (50-50)
RAP (CO)
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 38/43
Compaction Curve: RCA (MN) Blend
18
19
20
21
22
0 2 4 6 8 10 12 14 16
Dry
Weig
ht,
(kN
/m3)
Water Content (%)
Class 5 (MN)
Blend (50-50)
RCA (MN)
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 39/43
100
200
300
400
500
600
700
800
RAP (CA)
RAP (CO)
0 50 100
Inte
rnal S
RM
(M
Pa)
RAP or RCA (%)
RCA (MN)
SRM of Blends
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 40/43
0.5
1
1.5
2
RAP (CA)
RAP (CO)
0 50 100
SR
M B
len
d/S
RM
Cla
ss 5
RAP or RCA (%)
RCA (MN)
Results
RCA 30% increase
RAP 68%
increase
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 41/43
Conclusions
Freeze-thaw cycling reduces SRM of RAP and natural aggregate.
• The modulus loss of RAP over 20 cycles is comparable to that of natural aggregate (i.e., 28% vs 21%).
• RAP with finer gradation experienced more modulus loss, mostly in 1st 5 cycles.
Consistent RCA trend with freeze-thaw cycling
• Modulus decreases up to 5 cycles, then
• Modulus increases up to 20 cycles
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 42/43
Conclusions continued
Seismic modulus testing confirmed resilient modulus trend of RCA due to freeze-thaw:
• A convenient non-destructive test to evaluate the effect of freeze thaw cycling on RCA and natural aggregate.
• Does not work with RAP.
Reduction of relative compaction from 95% to 85% reduces the SRM of RAP, RCA and natural aggregate with comparable average rates (i.e., 37%, 41%, and 47%, respectively).
• One RAP sample showed greater sensitivity.
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 43/43
Conclusions continued
Increase of compaction moisture content from 2% dry to 2% wet of OMC (4% change) reduces the SRM of RAP and RCA by 40%.
• RCA showed greater sensitivity than RAP.
Blending recycled materials with natural aggregate result in intermediate modulus between the moduli of two materials.
• Recycled materials has higher moduli than natural aggregate thus blends increase modulus.
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 44/43
Thank You
• Special thanks to: • Dr. Tuncer Edil
• Dr. Craig Benson
• Dr. Dante Fratta
• Ozlem Bozyurt
• Andrew Keene
• Ryan Shedivy
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 45/43
Waste Pavement Material Breakage process
Recycled Materials
Pavement constructed using recycled materials
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 46/43
Questions?
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 47/43
Results: Compaction Moisture Effect
100
200
300
400
500
600
4 6 8
RCA (CO)
RCA (OH)
Absorption (%)
Inte
rnal S
RM
(M
Pa)
Finer
Medium
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 48/43
Results: Compaction Moisture Effect
2
4
6
8
10
12
14
16
4 6 8
RCA (CO)-Before
RCA (CO)-After
RCA (OH)-Before
RCA (OH)-After
Absorption (%)
Wate
r C
onte
nt (
%)
Finer Medium
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 49/43
Seismic Test Method
t1 t2
Time, t
Voltage
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 50/43
Compaction Curves of Representative Materials
18
19
20
21
22
0 2 4 6 8 10 12 14 16
Dry
We
ight, (
kN
/m3)
Water Content (%)
Class 5 (MN)
RAP (MN)
RAP (CA)
RAP (TX)
RCA (CA)
RCA (MI)
RCA (TX)
October 4, 2011 Unbound Recycled Material Jim Tinjum, PhD, PE University of Wisconsin-Madison Slide 51/43
The change in the fine percentage
Specimens
Before
Compaction
After
Compaction
Fines (%) Fines (%)
RCA (CA) 0.97 2.52
RCA (CO) 7.59 7.80
RCA (MI) 0.80 3.30
RCA (TX) 3.80 7.37
Class 5 (MN) 1.84 4.59
RAP (CA) 1.70 1.86
RAP (MN) 1.30 4.91
RAP (OH) 0.81 2.09
RAP (TX) 1.09 1.92 *Dry PSD before and after compaction