Georgia’s Experience With Crumb Rubber in Hot-Mix Asphalt

1997 ◽  
Vol 1583 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Dan R. Brown ◽  
David Jared ◽  
Chris Jones ◽  
Don Watson
Keyword(s):  
Test Section ◽  
Hot Mix Asphalt ◽  
Crumb Rubber ◽  
Vacuum Extraction ◽  
Department Of Transportation ◽  
Reflective Cracking ◽  
Ground Tire Rubber ◽  
Asphalt Cement ◽  
Wet Process ◽  
Henry County

In 1991, the Georgia Department of Transportation (GDOT) began to evaluate the production and placement of crumb rubber hot-mix asphalt. The crumb rubber mix (CRM) used by GDOT was produced by adding ground tire rubber to hot-mix asphalt using the wet process. A test section of CRM was placed on I-75 in Henry County, just south of Atlanta, consisting of a surface mix containing 6 percent crumb rubber by weight of asphalt cement (AC). The test section was evaluated from 1991 to 1995. The test section indicated that the CRM became very brittle over time, as indicated by a large increase in viscosity and decrease in penetration, and by a large amount of transverse reflective cracking. Compared with the control mix, the CRM did not reduce rutting and was more than twice as expensive to place. In addition to the test section, two contract projects were initiated using CRM. These two projects indicated that CRM could be produced and placed using conventional equipment requiring only a few modifications. On-site blending units were used to combine the crumb rubber at a dosage rate of 16 percent by weight of AC. Pump and metering equipment was modified to accurately meter the stiff asphalt material, and correction factors were established for determining the AC content by vacuum extraction, since some of the rubber particles were retained in the aggregate portion of the sample.

Flagstaff I-40 Asphalt Rubber Overlay Project: Nine Years of Success

2000 ◽  
Vol 1723 (1) ◽  
pp. 45-52 ◽  
Author(s):  
George B. Way
Keyword(s):  
Large Scale ◽  
Skid Resistance ◽  
Department Of Transportation ◽  
Reflective Cracking ◽  
Construction Time ◽  
Ground Tire Rubber ◽  
Cracked Concrete ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Test Project

In 1990 the Arizona Department of Transportation designed and constructed a large-scale asphalt rubber (AR) test project in Flagstaff, Arizona, on the very heavily trafficked Interstate 40. The purpose of the test project was to determine whether a relatively thin overlay with AR could reduce reflective cracking. AR is a mixture of 80 percent hot paving-grade asphalt and 20 percent ground tire rubber. This mixture is also commonly referred to as the asphalt rubber wet process or McDonald process. The overlay project was built on top of a very badly cracked concrete pavement that was in need of reconstruction. The AR overlay has performed beyond original expectations. After 9 years of service the overlay is still virtually crack free, with good ride, virtually no rutting or maintenance, and good skid resistance. The benefits of using AR on this project represent about $18 million in construction savings and 4 years’ less construction time. Strategic Highway Research Program SPS-6 test sections built in conjunction with the project further illustrate the very good performance of AR. Results of this project have led to widespread use of AR hot mixes throughout Arizona. On the basis of this work over 3333 km (2,000 mi) of successfully performing AR pavements have been built since 1990.

Arkansas Experience with Crumb Rubber Modified Mixes Using Marshall and Strategic Highway Research Program Level I Design Methods

1996 ◽  
Vol 1530 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Gary V. Gowda ◽  
Kevin D. Hall ◽  
Robert P. Elliott
Keyword(s):  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Heavy Traffic ◽  
Percent Level ◽  
Crumb Rubber ◽  
Aggregate Gradation ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Level I

Unmodified and crumb rubber modified mixes conforming to the Arkansas State Highway and Transportation Department Type II surface course specifications were designed for heavy traffic conditions and environmental conditions typical to Arkansas by using the Marshall and Superpave Level I methods. Specimens prepared at appropriate design asphalt contents were evaluated for both volumetric and performance considerations. Three mix types, an unmodified hot-mix asphalt concrete, a dry process rubber modified asphalt, and a wet process asphalt rubber, were included in the investigation. For the asphalt cement, crumb rubber, aggregate type, and aggregate gradation used, the design asphalt content and the VMA were reduced for the SHRP Level I method relative to the Marshall method. Incorporation of crumb rubber into hot-mix asphalt concrete provided increased rutting resistance; however, the rubber modified mixes did not show enhanced resilient and tensile properties when tested at 25°C. Also, the performance-related properties of the SHRP Level I asphalt-rubber mixes (5, 10, and 15 percent A-R blends) evaluated did not differ significantly at 5 percent level of significance.

Georgia’s Experience with Recycled Roofing Shingles in Asphaltic Concrete

1998 ◽  
Vol 1638 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Donald E. Watson ◽  
Andrew Johnson ◽  
Hem R. Sharma
Keyword(s):  
Test Section ◽  
Building Materials ◽  
Asphalt Pavement ◽  
Cost Savings ◽  
Reclaimed Asphalt Pavement ◽  
Fine Aggregate ◽  
Asphaltic Concrete ◽  
Department Of Transportation ◽  
Reclaimed Asphalt ◽  
Asphalt Cement

Reuse of roofing shingle waste not only minimizes the environmental problems related to the disposal of waste in landfills, but also reduces the amount of virgin asphalt cement and fine aggregate required in hot mix asphaltic concrete (HMAC), thus creating the potential for cost savings. The Georgia Department of Transportation (GDOT) has experimented with the recycling of roofing shingles in HMAC by constructing two test sections in 1994 and 1995. The source of the roofing shingles used in both test sections was waste generated by a roofing manufacturer; this generally consisted of discolored or damaged shingles. One test section was constructed on Chatham Parkway in Chatham County and one on State Route 21 in Effingham County. GAF Building Materials, Inc., located in Savannah, provided the waste shingle material; APAC Georgia, Inc., also located in Savannah, produced and placed these experimental mixtures. To date, both test sections are performing well compared with the unmodified control sections. Based on the performance of these test sections, shingle manufacturing waste is allowed as a recycling material in HMAC, just as reclaimed asphalt pavement is, for GDOT projects. A specification allowing postconsumer roofing shingle waste to be used is also being proposed.

Performance Analysis of Ultrathin Whitetopping Intersections on US-169: Elk River, Minnesota

2003 ◽  
Vol 1823 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Julie M. Vandenbossche
Keyword(s):  
Test Section ◽  
Hot Mix Asphalt ◽  
Asphalt Pavements ◽  
Department Of Transportation ◽  
Uniform Thickness ◽  
Research Facility ◽  
Transverse Cracks ◽  
Elk River ◽  
Joint Pattern

The Minnesota Department of Transportation constructed an ultrathin whitetopping (UTW) project at three consecutive intersections on US-169 at Elk River, Minnesota, to gain more experience with both the design and the performance of UTW. Distinct cracking patterns developed within each test section. The UTW test sections with a 1.2- ×1.2-m (4- ×4-ft) joint pattern included corner breaks and transverse cracks. Corner breaks were the primary distress in the test section with a 1.8- ×1.8-m (6- ×6-ft) joint pattern, although very little cracking was exhibited. The Minnesota Road Research Facility UTW test sections on I-94 allow comparisons of the same UTW design on hot-mix asphalt (HMA) pavements with different structural capacities to be made. The strain and deflection measurements emphasize the importance of the support provided by the HMA layer. A reduction in this support occurs when the temperature of the HMA is increased or when the HMA begins to ravel. During evaluations of whether UTW is a viable rehabilitation alternative, cores should be pulled from the pavement to determine if the asphalt is stripping and if the asphalt layer has adequate thickness. UTW can be successfully placed on as little as 76 mm (3 in.) of asphalt, if the quality of the asphalt is good. The cores should also reveal whether the asphalt layer is of uniform thickness and whether stripping and raveling have occurred. If the asphalt layer is of uniform thickness and stripping and raveling have not occurred, UTW is a good option for use in the rehabilitation of asphalt pavements.

Influence of crumb rubber size particles on moisture damage and strength of the hot mix asphalt

2021 ◽  
Author(s):  
Munder Bilema ◽  
Mohamad Aman ◽  
Norhidayah Hassan ◽  
Mohamed Haloul ◽  
Saeed Modibbo
Keyword(s):  
Hot Mix Asphalt ◽  
Moisture Damage ◽  
Crumb Rubber

scholarly journals Dataset of mechanical, marshall and rheological properties of crumb rubber – Bio-oil modified hot mix asphalt for sustainable pavement works

Data in Brief ◽  
2018 ◽  
Vol 21 ◽  
pp. 63-70 ◽  
Author(s):  
Abayomi Emmanuel Modupe ◽  
Olumoyewa Dotun Atoyebi ◽  
Opeyemi Emmanuel Oluwatuyi ◽  
Oluwasegun James Aladegboye ◽  
Ayobami Adebola Busari ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Hot Mix Asphalt ◽  
Crumb Rubber ◽  
Bio Oil

Cost-Effectiveness of Paving Fabrics Used to Control Reflective Cracking

2000 ◽  
Vol 1730 (1) ◽  
pp. 139-149 ◽  
Author(s):  
William G. Buttlar ◽  
Diyar Bozkurt ◽  
Barry J. Dempsey
Keyword(s):  
Life Cycle ◽  
Cost Effectiveness ◽  
Department Of Transportation ◽  
Reflective Cracking ◽  
Crack Control ◽  
Condition Rating ◽  
System A ◽  
Rigid Pavements ◽  
The Cost ◽  
And Control

The Illinois Department of Transportation (IDOT) spends $2 million annually on reflective crack control treatments; however, the cost-effectiveness of these treatments had not been reliably determined. A recent study evaluated the cost-effectiveness of IDOT reflective crack control System A, which consists of a nonwoven polypropylene paving fabric, placed either in strips longitudinally over lane-widening joints or over the entire pavement (area treatment). The study was limited to projects constructed originally as rigid pavements and subsequently rehabilitated with one or more bituminous overlays. Performance of 52 projects across Illinois was assessed through crack mapping and from distress and serviceability data in IDOT’s condition rating survey database. Comparisons of measured reflective cracking in treated and control sections revealed that System A retarded longitudinal reflective widening crack development, but it did not significantly retard transverse reflective cracking, which agrees with earlier studies. However, both strip and area applications of these fabric treatments appeared to improve overall pavement serviceability, and they were estimated to increase rehabilitation life spans by 1.1 and 3.6 years, respectively. Reduction in life-cycle costs was estimated to be 4.4 and 6.2 percent when placed in medium and large quantities, respectively, and to be at a break-even level for small quantities. However, life-cycle benefits were found to be statistically insignificant. Limited permeability testing of field cores taken on severely distressed transverse joints suggested that waterproofing benefits could exist even after crack reflection. This was consistent with the observation that, although serviceability was generally improved with area treatment, crack reflection was not retarded relative to untreated areas.

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