Maintaining OGFC Pavements AWS
Laboratory Evaluation of Fog Seal Treatment of Open-Graded Friction Course Mark Woods Matthew Chandler Tennessee Department of Transportation Weimin Song Xiang Shu Baoshan Huang The University of Tennessee, Knoxville
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Outline • Introduction OGFC Fog seal treatment of OGFC • Objective • Laboratory tests Permeability test Texture depth test Loaded wheel abrasion test • Summary and conclusions Powerpoint Templates
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Introduction OGFC? • • •
A special purpose mixture intended for higher internal air voids and better friction characteristics. Consist of an open gradation, mostly of coarse size aggregate with little fines. Benefits of OGFC No hydroplaning Reduced splash and spray Improved skid resistance Increased Safety
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Introduction Disadvantages of OGFC • • •
More expensive More prone to fail – cracking & raveling Shorter service life
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Introduction Fog seal treatment of OGFC • • •
Location: I40 (Mile 61) (near Jackson, TN) Date: Oct. 19 2016 Pavement length of fog seal treatment: 300 m
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Introduction Field application of fog seal • •
•
Fog seal: water-based asphalt emulsion, containing rejuvenator Fog seal application rate: Shoulder: 0.59, 0.36 L/m2 (0.13, 0.08 gal/yd2) Lane: 0.45 L/m2 (0.10 gal/yd2) Cores taken before and after treatment
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Introduction Field application of fog seal • • •
Core number: 24 Samples were obtained 1.5 hours after fog seal treatment. Depth of OGFC: 3.2 cm (1 ¼ in)
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Objective To evaluate the effect of fog seal treatment on OGFC: • Water permeability • Texture depth • Durability
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Laboratory tests Modified permeability test • •
High permeability is the basic requirement of OGFC. Time required for water to drop from the upper to the bottom is recorded for permeability analysis.
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Laboratory tests Permeability test •
•
Before fog seal treatment: Permeability in the lane is better than in the shoulder. (High speed traffic helps keep the pores from clogging with debris) After fog seal treatment: Fog seal application decreased the permeability both in the lane and the shoulder.
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Laboratory tests Texture depth test • • •
Texture depth affects the skid-resistance, especially in rainy days. Texture depth test was performed according to ASTM E 965. Texture depth is the ratio between sand volume to the covered area.
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Laboratory tests Texture depth test • •
The application of fog seal decreased the texture depth of both of the lane and shoulder. As fog seal application rate increased, the texture depth decreased.
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Laboratory tests Loaded wheel abrasion test • •
• • •
The Asphalt Pavement Analyzer (APA) is used to simulate the field traffic condition to evaluate the durability. Steel studs (2 mm in diameter and 3 mm in height) were embedded into the initially smooth rubber surface to make the abrasion more harsh. Wheel load: 890 N 12000 cycles at a frequency 2 cycles/second Temperature: 20 °C
(a) APA
Powerpoint Templates (b) Wheel
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Laboratory tests Loaded wheel abrasion test Weight loss:
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Laboratory tests Loaded wheel abrasion test • •
When no fog seal was applied, the abrasion loss was about 0.8%. The application of fog seal significantly reduced the abrasion loss, indicating that fog seal could help reduce raveling and improve the durability of OGFC.
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Laboratory tests Loaded wheel abrasion test • •
Texture depth test was conducted again after the loaded wheel abrasion test . Results show that the texture depth increased after the loaded wheel test.
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Summary and conclusions • • •
•
Before fog seal treatment, samples from the lane showed a higher permeability than those from the shoulder. Fog seal application decreased the permeability of both the lane and the shoulder. Fog seal decreased the texture depth of both the lane and the shoulder. But after the loaded wheel abrasion test, the texture depth increased. Fog seal significantly reduced the abrasion loss, indicating that fog seal could help reduce raveling and improve the durability of OGFC.
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Thank You!
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Powerpoint Templates
1
Outline • Introduction OGFC Fog seal treatment of OGFC • Objective • Laboratory tests Permeability test Texture depth test Loaded wheel abrasion test • Summary and conclusions Powerpoint Templates
2
Introduction OGFC? • • •
A special purpose mixture intended for higher internal air voids and better friction characteristics. Consist of an open gradation, mostly of coarse size aggregate with little fines. Benefits of OGFC No hydroplaning Reduced splash and spray Improved skid resistance Increased Safety
Powerpoint Templates
3
Introduction Disadvantages of OGFC • • •
More expensive More prone to fail – cracking & raveling Shorter service life
Powerpoint Templates
4
Introduction Fog seal treatment of OGFC • • •
Location: I40 (Mile 61) (near Jackson, TN) Date: Oct. 19 2016 Pavement length of fog seal treatment: 300 m
Powerpoint Templates
5
Introduction Field application of fog seal • •
•
Fog seal: water-based asphalt emulsion, containing rejuvenator Fog seal application rate: Shoulder: 0.59, 0.36 L/m2 (0.13, 0.08 gal/yd2) Lane: 0.45 L/m2 (0.10 gal/yd2) Cores taken before and after treatment
Powerpoint Templates
6
Introduction Field application of fog seal • • •
Core number: 24 Samples were obtained 1.5 hours after fog seal treatment. Depth of OGFC: 3.2 cm (1 ¼ in)
Powerpoint Templates
7
Objective To evaluate the effect of fog seal treatment on OGFC: • Water permeability • Texture depth • Durability
Powerpoint Templates
8
Laboratory tests Modified permeability test • •
High permeability is the basic requirement of OGFC. Time required for water to drop from the upper to the bottom is recorded for permeability analysis.
Powerpoint Templates
9
Laboratory tests Permeability test •
•
Before fog seal treatment: Permeability in the lane is better than in the shoulder. (High speed traffic helps keep the pores from clogging with debris) After fog seal treatment: Fog seal application decreased the permeability both in the lane and the shoulder.
Powerpoint Templates
10
Laboratory tests Texture depth test • • •
Texture depth affects the skid-resistance, especially in rainy days. Texture depth test was performed according to ASTM E 965. Texture depth is the ratio between sand volume to the covered area.
Powerpoint Templates
11
Laboratory tests Texture depth test • •
The application of fog seal decreased the texture depth of both of the lane and shoulder. As fog seal application rate increased, the texture depth decreased.
Powerpoint Templates
12
Laboratory tests Loaded wheel abrasion test • •
• • •
The Asphalt Pavement Analyzer (APA) is used to simulate the field traffic condition to evaluate the durability. Steel studs (2 mm in diameter and 3 mm in height) were embedded into the initially smooth rubber surface to make the abrasion more harsh. Wheel load: 890 N 12000 cycles at a frequency 2 cycles/second Temperature: 20 °C
(a) APA
Powerpoint Templates (b) Wheel
13
Laboratory tests Loaded wheel abrasion test Weight loss:
Powerpoint Templates
14
Laboratory tests Loaded wheel abrasion test • •
When no fog seal was applied, the abrasion loss was about 0.8%. The application of fog seal significantly reduced the abrasion loss, indicating that fog seal could help reduce raveling and improve the durability of OGFC.
Powerpoint Templates
15
Laboratory tests Loaded wheel abrasion test • •
Texture depth test was conducted again after the loaded wheel abrasion test . Results show that the texture depth increased after the loaded wheel test.
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Summary and conclusions • • •
•
Before fog seal treatment, samples from the lane showed a higher permeability than those from the shoulder. Fog seal application decreased the permeability of both the lane and the shoulder. Fog seal decreased the texture depth of both the lane and the shoulder. But after the loaded wheel abrasion test, the texture depth increased. Fog seal significantly reduced the abrasion loss, indicating that fog seal could help reduce raveling and improve the durability of OGFC.
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17
Thank You!
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