Road Science Presentation Template - TSP2
Road Science Presentation Template - TSP2
Road Science Presentation Template - TSP2
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Bonded Wearing Course<br />
and Bonded Pavements<br />
1
US 50 Lake Tahoe<br />
California<br />
Michigan M-25<br />
US 69 Beaumont, Texas<br />
2
A Solution<br />
For Lower Life Cycle Cost,<br />
Longer Lasting <strong>Road</strong>s<br />
Problems:<br />
• Noisy pavements<br />
• Overhead clearances, curb reveal<br />
• Backs pray vis ibility<br />
• Loss of macro-texture<br />
• Long construction delays<br />
• Need for cost effective surfacing<br />
Solution: Bonded Wearing Course<br />
3
What is BWC?<br />
Hot mix asphalt surface treatment<br />
• Preventive maintenance<br />
• Corrective maintenance<br />
• Surface for new pavements<br />
• Over PCC or asphalt pavements<br />
• ~50% of projects over PCC, ~50% over asphalt<br />
Single pass system<br />
• Polymer modified emulsion membrane<br />
• Thin gap graded hot mix<br />
• Placed with spray paver<br />
4
A Little History. . .<br />
1988 - Firs t Trial in France<br />
1992 - Introduced in U.S<br />
1992 - Projects in TX & AL<br />
1993 - Projects in NJ & PA<br />
1993-97 - Projects in Northeast<br />
1998 - Process adapted & spread throughout U.S.<br />
5
Spray Paver<br />
3 Processes<br />
• Spray emulsion<br />
• Lay hot mix<br />
• Smooth the mat<br />
Application<br />
of emulsion<br />
Application<br />
of HMA<br />
6
Spray Paver<br />
Thin mat overlay<br />
60-100 ft/min<br />
Minimum of stops<br />
Uniform application of emulsion<br />
7
Polymer<br />
Modified Emuls ion<br />
Special polymer membrane<br />
Controls migration into mix<br />
Superior bonding<br />
• Allows thin lifts without<br />
• delamination<br />
Seals existing pavement<br />
8
The Hot Mixed Asphalt<br />
High quality aggregate<br />
• Durable macro-texture & skid resistance<br />
Gap graded<br />
Mix designed for process<br />
9
The HMA Binder<br />
PG binders<br />
Polymer modified<br />
asphalt binders<br />
• Less draindown<br />
• Quicker traffic return<br />
• Improved adhesion<br />
• Less water sensitivity<br />
• Better cracking resistance<br />
• More durable<br />
10
Typical Aggregate Gradation<br />
Gap Graded<br />
• Similar to Stone Matrix Asphalt gradation<br />
• Enough space for polymer modified asphalt emulsion<br />
membrane<br />
• Insures stone on stone contact<br />
• Allows moisture to drain off<br />
• Fines are part of asphalt binder mastic<br />
11
Typical Aggregate Gradation<br />
100<br />
90<br />
80<br />
Type B<br />
Percent Passing<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
.075<br />
.30<br />
.150<br />
Sieve Size (mm) Raised to 0.45 Power<br />
Type B min<br />
Type B max<br />
.60 1.18 2.36 4.75<br />
9.50 12.5<br />
12
Other Typical Gradations<br />
100<br />
12.5 mm Nominal Sieve Size<br />
Percent Passing<br />
80<br />
60<br />
40<br />
20<br />
Type A<br />
Type A Max<br />
Type A Min<br />
0<br />
.075 .15 .3 .60 1.18 2.36 4.75 9.50 12.5 19.0<br />
Sieve Size (mm) Raised to 0.45 Power<br />
13
Other Typical Gradations<br />
12.5 mm Nominal Sieve Size<br />
100<br />
Percent Passing<br />
80<br />
60<br />
40<br />
20<br />
Type C<br />
Type C Max<br />
Type C Min<br />
0<br />
.075 .15 .3 .60 1.18 2.36 4.75<br />
9.50 12.5 19.0<br />
Sieve Size (mm) Raised to 0.45 Power<br />
14
Other Spray Paver Mixes<br />
Open Graded Friction Courses (OFGC)<br />
• Permeable friction course<br />
• Porous friction course<br />
• Wet process crumb rubber open graded and gap graded mixes<br />
• Terminal blend crumb rubber open graded and gap graded mixes<br />
15
Typical Coarse Aggregate<br />
Specifications<br />
Los Angeles abrasion value 1 , % loss<br />
35 max<br />
Soundness 1 , % loss Magnesium Sulfate or<br />
Sodium Sulfate<br />
18 max<br />
12 max<br />
Flat & Elongated Ratio at 3:1<br />
25% max<br />
% Crushed, single face 95 min<br />
% Crushed, ≥ 2 mechanically crushed faces 85 min<br />
Micro-Deval, % loss<br />
18 max<br />
1<br />
LA & Soundness targets for selection<br />
Not sole basis for rejection<br />
16
Typical Fine Aggregate<br />
Specifications<br />
Sand Equivalent<br />
45 min<br />
Methylene Blue (materials passing 200)<br />
10 max<br />
Uncompacted Void Content<br />
40 min<br />
17
Benefits of Both<br />
SMA & OGFC<br />
Advantages of Stone Matrix Asphalt (SMA) at interface<br />
• Thick polymer mastic (extra asphalt from membrane)<br />
• Stone on stone contact<br />
Advantages of Open Graded Friction Course (OGFC) at surface<br />
• Porous mix reduces backspray & tire noise<br />
• High macro-texture<br />
Ultrathin Open Mix<br />
Polymer Membrane<br />
“Best of Both Worlds”<br />
18
Application Rates<br />
Emulsion membrane<br />
• 0.13 - 0.3 gal/yd 2<br />
Ultrathin hot mix asphalt overlay<br />
• Type A (4.75 mm) - 50-70 lbs /yd 2<br />
• Type B (9.5 mm) - 75-85 lbs /yd 2<br />
• Type C (12.5 mm) - 85-95 lbs /yd 2<br />
Total thickness: ½ to 1 inch<br />
19
The Process (Type B)<br />
The emulsion membrane “wicks up”<br />
around the HMA aggregates<br />
5/8” minimum<br />
depth of mix<br />
3/8” nominal<br />
aggregate size<br />
3/16”emulsion<br />
membrane depth<br />
The emulsion cures,<br />
bonding the mix & pavement<br />
9-12 µm<br />
coating on<br />
aggregates<br />
Existing Pavement<br />
20
The Process<br />
21
Performance<br />
US 281 San Antonio, TX after 12 years<br />
22
Reduced Tire Splash<br />
Backspray from dense graded<br />
surface<br />
Reduced backspray on Bonded<br />
Wearing Course<br />
Results depend upon quality and gradation of aggregates used<br />
23
I-81 Virginia<br />
Dense graded surface<br />
Ultrathin Bonded Wearing<br />
Course<br />
Results depend upon quality and gradation of aggregates used<br />
24
Open Mix Surfaces<br />
Reduce noise<br />
Minimize backs pray<br />
Increas e vis ibility<br />
Courtesy Asphalt Institute<br />
25
How Do We Quantify Nois e?<br />
The Decibel Scale<br />
Sound<br />
Pressure<br />
N/sq. , m.<br />
1000<br />
100<br />
10<br />
1<br />
0.1<br />
0.01<br />
0.001<br />
0.0001<br />
0.00001<br />
0.000001<br />
Hearing Threshold<br />
Logarithmic scale<br />
Conversation<br />
Discomfort<br />
Pain Threshold<br />
0 20 40 60 80 100 120 140<br />
Decibel Level<br />
Courtesy Asphalt Institute<br />
26
The Decibel Scale<br />
67 dB(A)<br />
50 ft<br />
Courtesy Asphalt Institute<br />
27
Reduction of 3 dB(A) is Like Doubling Distance From the Noise<br />
67 dB(A)<br />
- 3 dB(A) = 64 dB(A)<br />
100 ft<br />
A 3dB(A) reduction corresponds to:<br />
• Doubling the distance<br />
• Reducing traffic volume by 50%<br />
• Reducing traffic speed by 25%<br />
Courtesy Asphalt Institute<br />
28
Reduced Tire Noise<br />
Garden State Parkway<br />
New Jersey<br />
(150,000 ADT)<br />
Over PCC<br />
Over bituminous<br />
pavement<br />
Reduction in measured<br />
noise level by NovaChip<br />
surfacing<br />
3.2 – 4.1 dB<br />
1.4 – 2.1 dB<br />
Schmidt & Fischer, TRB, 1994<br />
29
NCAT Nois e Study<br />
for Michigan DOT<br />
Measured Tire Noise, dB(A)<br />
100<br />
99<br />
98<br />
97<br />
96<br />
95<br />
BWC Stone MatrixDense<br />
Asphalt Graded<br />
Asphalt<br />
Average of measurements at 60 mph<br />
12 pavement surfaces in Michigan<br />
2 types of tires<br />
Portland<br />
Cement<br />
Concrete<br />
NCAT Report to MDOT, 2003<br />
30
Durable Skid Resistance<br />
PA SR 422<br />
(28,000 ADT, 8% trucks)<br />
UTBWC Over PCC<br />
When<br />
tested<br />
Ave. Skid #<br />
ASTM E-274<br />
Before 27<br />
After 46<br />
+ 1 yr 56<br />
+ 2 yrs 54<br />
+ 5 yrs 57<br />
Pavement Skid Friction -<br />
Pennsylvania SR 512<br />
NB SB<br />
Pre UTBWC 49 48<br />
After UTBWC 46 44<br />
1 Year 54 53<br />
2 Years 54 53<br />
3 Years 60 59<br />
4 Years 58 58<br />
5 Years 55 55<br />
PennDOT Reports<br />
31
Other Benefits<br />
Protects pavement<br />
• Seals out water<br />
• Resists wear & rutting<br />
• Projects have lasted 10+ years<br />
with crack sealing<br />
• Resists top-down cracking<br />
Thin lift retains clearances, curbs<br />
Fast construction reduces user delays<br />
Night construction<br />
Lower life cycle costs<br />
32
Bonded Wearing Course Over Reconstruction<br />
I-35, north of Albert Lea, MN<br />
Seals and protects construction joints<br />
Centerline<br />
construction<br />
joint<br />
protected by<br />
BWC seal<br />
Cracks forming<br />
in unprotected<br />
construction<br />
joint<br />
on adjacent<br />
highway<br />
without BWC<br />
I-35 after 2½ years<br />
33
Field Trial<br />
Research Reports<br />
Caltrans Technical Advisory Guide<br />
Louisiana Transportation Research Center (LTRC) at LSU<br />
Texas Transportation Institute (TTI) at Texas A&M<br />
National Center for Asphalt Technology (NCAT) at Auburn<br />
Univers ity<br />
Pennsylvania DOT<br />
Mis s is s ippi DOT<br />
New Jersey Garden State Parkway<br />
Transportation Research Board (TRB) Record 2001<br />
34
Projects<br />
35
City of Lancas ter, California<br />
Residential neighborhood construction<br />
36
Res idential Cul-de-sac<br />
37
Brown Deer, WI<br />
Kent County, MI<br />
St. Paul, MN<br />
I-85 North Carolina<br />
38
San Jose, CA<br />
Birmingham, AL<br />
39
NCAT Tes t Track<br />
Restoring Skid Resistance<br />
1st Maintenance Treatment<br />
Polished<br />
surface<br />
prior to<br />
surfacing<br />
UTBWC<br />
surface<br />
“Excellent performance after 2,400,000<br />
ESALs, and still going”<br />
40
US 24<br />
Colorado Springs, CO<br />
41
US 25<br />
Kentucky<br />
42
Hanging Lake Tunnel, I-70<br />
Glenwood Springs, CO<br />
43
Harmon St. Las Vegas, NV<br />
Over New Construction<br />
44
Clark County Nevada<br />
Ultrathin Bonded Wearing Course<br />
Over New Construction<br />
Surface<br />
characteristics<br />
• Open graded<br />
• Bonded<br />
Durability<br />
• Longest lasting<br />
surface treatment<br />
Polymer emulsion<br />
membrane seals & protects<br />
• Seals surface imperfections<br />
• & cold joints<br />
Structural addition<br />
• Structural layer coefficient = 0.45<br />
45
US 50 Lake Tahoe, CA<br />
After 2 Years of Chains, Traffic & Snowplows<br />
With Bonded<br />
Wearing Course<br />
Without Bonded<br />
Wearing Course<br />
46
Los Angeles County, CA<br />
47
Night Paving<br />
San Antonio, Texas<br />
48
I-20/59 Birmingham, AL<br />
160,000 ADT<br />
Before surfacing<br />
After 3 years<br />
49
I-35 Denton, Texas<br />
I-35E Denton, Texas<br />
50
I-85 North Carolina<br />
after 1 year<br />
51
Stiles Rd Savannah, GA<br />
After 2 years<br />
After 1 year<br />
52
I-40 North Carolina<br />
After 4 years<br />
53
I-440 & I-64 North Carolina<br />
Over PCC After 3 years<br />
54
SR 1/64 Raleigh, NC<br />
After 7 years<br />
55
Rt. 422 Pennsylvania<br />
After 10 years<br />
56
Where do you place BWC?<br />
Site Selection Guidelines over Asphalt Pavements<br />
Structurally sound pavement<br />
Rut depth < 12.5 mm or ½ inch<br />
Minor to moderate severity transverse & longitudinal cracking<br />
Minor to moderate severity patches & bleeding<br />
Raveling & polished aggregate to high severity<br />
57
Where do you place BWC?<br />
Site Selection Guidelines over PCC<br />
Structurally sound pavement<br />
Low severity “D” cracking<br />
Minor to moderate transverse & longitudinal cracking<br />
Minor to moderate severity corner breaks<br />
Minor to moderate severity joint spalling<br />
Map cracking < 10 m 2 in any 100 m 2 area<br />
Faulting < 9.5 mm<br />
No blowups, water<br />
bleeding or pumping<br />
I-40 North Carolina<br />
58
Poor Candidates for Maintenance BWC<br />
Possible candidates for Rehab Bonded Pavement<br />
High severity alligator cracking<br />
High severity block cracking<br />
Rutting<br />
High severity “D” cracking<br />
59
Pavement Preparation<br />
Clean pavement<br />
Seal existing cracks > ¼ inch<br />
• Don’t overfill<br />
Fill s urface deformities > ½ inch deep<br />
Protect manhole covers, drains, etc.<br />
Remove pavement markings if possible (for best ride<br />
quality)<br />
60
Preventive Maintenance<br />
I-70 Kansas<br />
61
Rte. 288 Virginia<br />
Over New Construction After 1 Year<br />
62
Summary<br />
Thin lift<br />
Fast<br />
construction<br />
Cost<br />
effective<br />
Hot mix<br />
Minimal user<br />
delays<br />
Quiet - high<br />
macro-texture<br />
Waterproofs<br />
Preserves<br />
63
Thank you.<br />
Questions?<br />
64
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