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Mihai Marasteanu & Adam Summary of Shingles Work at Summary of Shingles Work at the University of Minnesota the University of Minnesota
Mihai Marasteanu & Adam Zofka
Summary of Shingles Work at Summary of Shingles Work at the University of Minnesota the University of Minnesota
IntroductionIntroduction
Two smaller projectsMissouri samples
–Mixture testingMinnesota samples
–Mixture and binder testing
Missouri Missouri SpecimenSpecimenss
Table 1. Test details
Mixture Temperature
Replicate
designation
Average Thickness
[mm]
Diameter [mm]
17 43 150 -10°C 18 42 150 11 43 150 12 44 150 -20°C 13 43 150 14 44 150 15 44 150
20% RAP PG 64-22
-30°C 16 42 150 27 44 150 -10°C 28 43 150 21 40 150 22 41 150 -20°C 23 44 150 24 41 150 25 42 150
20% RAP PG 58-28
-30°C 26 41 150 37 46 150 -10°C 38 42 150 31 41 150 32 41 150 -20°C 33 43 150 34 40 150 35 43 150
15% RAP + 5% shingles
PG 58-28
-30°C 36 42 150 47 46 150 -10°C 48 42 150 41 47 150 42 41 150 -20°C 43 43 150 44 45 150 45 46 150
15% RAP + 5% shingles
PG 64-22
-30°C 46 42 150
Creep Stiffness Results, PG 58-28Creep Stiffness Results, PG 58-28
6.1
11.5
17.3
8.1
16.6
21.4
0
10
20
30
-10C -20C -30C
Stif
fnes
s @
100
sec
20% RAPPG 58-28
15% RAP5% shing.PG 58-28
4.0
7.8
15.3
5.7
12.9
15.9
0
10
20
30
-10C -20C -30C
Stif
fnes
s @
500
sec
20% RAPPG 58-28
15% RAP5% shing.PG 58-28
Creep Stiffness Results, PG 64-22Creep Stiffness Results, PG 64-22
10.8 12.0
19.5
9.5
34.4 34.7
0
10
20
30
40
-10C -20C -30C
Stif
fnes
s @
100
sec
20% RAPPG 64-22
15% RAP5% shing.PG 64-22
7.48.9
16.4
5.9
27.530.3
0
10
20
30
40
-10C -20C -30C
Stif
fnes
s @
500
sec
20% RAPPG 64-22
15% RAP5% shing.PG 64-22
Strength Results, PG 58-28Strength Results, PG 58-28
4.1
4.5 4.44.4 4.54.5
0
3
6
-10C -20C -30C
Ten
sile
Str
engt
h [M
Pa]
20% RAPPG 58-28
15% RAP5% shing.PG 58-28
Strength Results, PG 64-22Strength Results, PG 64-22
4.54.9
3.94.3 4.2
4.7
0
3
6
-10C -20C -30C
Ten
sile
Str
engt
h [M
Pa]
20% RAPPG 64-22
15% RAP5% shing.PG 64-22
Conclusions Missouri SpecimensConclusions Missouri Specimens
For PG-22 mixture, at temperatures below -10°C, the addition of shingles increases the mixture stiffness considerablyMost likely results in increased thermal cracking and fatigue cracking occurrence
Also in PG-28 mixtures but to a much lesser extent
Strength properties were not significantly affected by the addition of shingles for both the PG-22 and PG-28 mixtures.
Conclusions Missouri SpecimensConclusions Missouri Specimens
Worth mentioning that during the cutting process, the saw shutoff automatically due to the intense heat generated when cutting the specimens prepared with shingles. This did not occur for the specimens prepared only with RAP.
Minnesota SpecimensMinnesota Specimens
Three types of materials20% reclaimed asphalt pavement (RAP),15% RAP + 5% Tear-off recycled asphalt shingles (RAS),
15% RAP + 5% Manufactured RAS. All three mixtures contain the same virgin
asphalt binder PG 58-28
Binders were chemically extracted (MnDOT) and tested (MnDOT + UMN)
Asphalt Mixture Creep StiffnessAsphalt Mixture Creep Stiffness
0.2
2.7
10.0
0.5
5.0
13.5
0.2
5.5
8.2
0
4
8
12
16
0 -10 -20
Temperature [oC]
Stif
fnes
s [G
Pa]
20% RAP
15% RAP + 5% Tear-off
15% RAP + 5% Manufactured
0.1
1.1
5.6
0.2
2.3
8.7
0.1
2.7
5.3
0
4
8
12
16
0 -10 -20
Temperature [oC]
Stif
fnes
s [G
Pa]
20% RAP
15% RAP + 5% Tear-off
15% RAP + 5% Manufactured
Asphalt Mixture StrengthAsphalt Mixture Strength
3.2
4.64.8
3.2
4.5
5.1
2.9
4.5
5.3
0.0
2.0
4.0
6.0
0 -10 -20
Temperature [oC]
Ten
sile
Str
engt
h [M
Pa]
20% RAP
15% RAP + 5% Tear-off
15% RAP + 5% Manufactured
Missouri vs. MinnesotaMissouri vs. Minnesota
6.1
11.5
10.0
8.1
16.6
5.0
13.5
2.7
0
4
8
12
16
20
-10C -20C
Temperature [oC]
Sti
ffn
ess
[GP
a]
20% RAP - MO
20% RAP - MN
15% RAP + 5% Tear-off - MO
15% RAP + 5% Tear-off - MN
4.0
7.8
5.65.7
12.9
2.3
8.7
1.1
0
4
8
12
16
20
-10C -20C
Temperature [oC]
Sti
ffn
ess
[GP
a]
20% RAP - MO
20% RAP - MN
15% RAP + 5% Tear-off - MO
15% RAP + 5% Tear-off - MN
Conclusions Minnesota Mix Conclusions Minnesota Mix SpecimensSpecimensAddition of tear-off RAS material increases
significantly the stiffness of the mixtures at all test temperaturesLargest increase at -20°C
Addition of manufactured RAS material increased stiffness only at 0°C and -10°CStiffness at -20°C reached the lowest observed value from all tested materials
Strength properties were not significantly affected by the addition of shingles
Conclusions Minnesota Mix Conclusions Minnesota Mix SpecimensSpecimensResults indicate lower stiffness values for the
Minnesota RAP mixtures compared to Missouri mixtures
Similar observation for the combinations of RAP + RASSuggests differences in the tear-off RAS materials used in the two studies
Minnesota Specimens – Extracted Minnesota Specimens – Extracted BindersBinders
Bending Beam Rheometer (BBR) tests were performed on the binders extracted
Direct Tension Tests (DTT) were performed at temperatures around the temperature at which S(60s) = 300MPa
Minnesota Specimens – Extracted Minnesota Specimens – Extracted BindersBinders
File name Temp Binder S @60 sec Average m-value @60sec AverageBC061CP.csv 107 0.303BC061CPB.csv 123 0.311BC061CPC.csv 206 0.264BC061CPD.csv 206 0.264BC062CPAA.csv 99 0.329BC062CPBB.csv 106 0.322BC062CPC.csv -18 182 182 0.289 0.289BC063APA.csv 173 0.325BC063APB.csv 166 0.322BC063APC.csv 313 0.237BC063APCC.csv 384 0.236BC063APD.csv 331 0.263BC063APDD.csv 288 0.264
0.250
0.307
0.264
0.326
0.324170
329
206
115
103
5% Tearoff 15%RAP
15% RAP 5% Manuf.
20% RAP
-12
-18
-12
-18
-24
0
50
100
150
200
250
300
350
5% Tearoff 15%RAP 15% RAP 5% Manuf. 20% RAP
S @
60se
c [M
Pa]
Higher temp.
Lower temp.
BBR ResultsBBR Results
Addition of shingles changes the propertiesLowers the stiffness!!!Lowers the m-values
–Changes the relaxation propertiesNeed to look at master curveNeed to look at thermal stresses
BBR Master CurvesBBR Master Curves
1
10
100
1,000
0 0 1 10 100 1,000 10,000
Time [sec]
Cre
ep S
tiffn
ess
[MP
a]
5% Tearoff 15%RAP
15% RAP 5% Manuf.
20% RAP Tref=-18C
BBR Master Curves – All MaterialsBBR Master Curves – All Materials
1
10
100
1,000
10,000
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
Time [sec]
Cre
ep S
tiffn
ess
[MP
a]
5% Tearoff 15%RAP15% RAP 5% Manuf.20% RAPShingles (287)Shingles (292)Demcon tearoff (301)Demcon tearoff (303)PG58-28 PAV
Tref = -18C
Thermal StressesThermal Stresses
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
-50 -40 -30 -20 -10 0 10 20 30
Temp [C]
Str
ess
[MP
a]
5% Tearoff 15%RAP
15% RAP 5% Manuf.
20% RAP
PG58-28 PAV
Direct Direct Tension Tension ResultsResults 0
1
2
3
4
0 1 2 3 4 5Strain, %
Str
ess
, MP
a
Rep 1, -24°CRep 2, -24°CRep 3, -24°CRep 1, -18°CRep 2, -18°CRep 3, -18°CRep 1, -12°CRep 2, -12°CRep 3, -12°C
20% RAP
0
1
2
3
4
0 1 2 3 4 5Strain, %
Str
ess
, MP
a
Rep 1, -24°CRep 2, -24°CRep 3, -24°CRep 1, -18°CRep 2, -18°CRep 3, -18°CRep 1, -12°CRep 2, -12°CRep 3, -12°C
15% RAP + 5% Manufactured
0
1
2
3
4
0 1 2 3 4 5Strain, %
Str
ess
, MP
a
Rep 1, -24°C
Rep 2, -24°C
Rep 3, -24°C
Rep 1, -18°C
Rep 2, -18°C
Rep 3, -18°C
Rep 1, -12°C
Rep 2, -12°C
15% RAP + 5% Tearoff
Critical TemperatureCritical Temperature
y = -0.0817x + 1.6667
R2 = 0.9142
0
2
4
6
8
10
12
14
-50 -40 -30 -20 -10 0 10 20 30
Temp [C]
Str
ess
[MP
a]
20% RAP
Strength
Linear (Strength)
Critical TemperatureCritical Temperature
y = -0.065x + 1.73
R2 = 0.998
0
2
4
6
8
10
12
-50 -40 -30 -20 -10 0 10 20 30
Temp [C]
Str
ess
[MP
a]
15% RAP 5% Manuf.
Strength
Linear (Strength)
Critical TemperatureCritical Temperature
y = -0.1167x + 0.1333
R2 = 0.9735
0
2
4
6
8
10
12
14
-50 -40 -30 -20 -10 0 10 20 30
Temp [C]
Str
ess
[MP
a]
5% Tearoff 15%RAP
Strength
Linear (Strength)
Conclusions - Binder ResultsConclusions - Binder Results
The two types of shingles perform differentlyThe manufactured material seems to be beneficial
–Decreases stiffness–Does not affect strength–Reduces critical temperature very little
The tear off affects properties in a negative way (although it also decreases stiffness)
–Lowers strength significantly–Increases critical temperature
Conclusions - Binder ResultsConclusions - Binder Results
The role of m-value not fully understoodSpec requires higher m-values (> 0.300)However, authors showed that lower m-values result in less thermal stress accumulation
Needs to be further investigated
The limited data also shows that binder and mixture results do not always agreeMost likely due to other parameters from mixture preparation (gradation, air voids, etc)
Thank you!Thank you!
