A-Z Index Calendar Campus Maps Phonebook Webcams
Join Our Mailing List and Register to Receive Our Email Newsletter

 

 

Research Projects

CRM Modified Porland Cement Concrete
An experimental program was undertaken to study the effect of two different types of crumb rubber i.e. Ambient and Cryogenic, to evaluate the effect of the different surface texture due to the manufacturing techniques. Plastic state properties such as air content, workability and unit weight were tested. Hardened concrete tests included compressive strength, freeze and thaw (F-T) test and hardened air content determination. The following variables were tested:

  1. Crumb rubber processing method (cryogenic vs. ambient)
  2. Amount of crumb rubber (8, 16, and 24%)
  3. Size of crumb rubber (#8, #50, and #100)

High-Temperature Properties of Crumb Rubber Modified (CRM) Asphalt Binder Study
This project involved the exploration of the effect of several different variables on the high-temperature properties of crumb rubber-modified asphalt binder. Several different binder sources were used in the study, as well as the following variables:

  1. Crumb rubber processing method (cryogenic vs. ambient)
  2. Amount of crumb rubber
  3. Size of crumb rubber
  4. Reaction time

Chemical Analysis of Crumb Rubber Modified (CRM) Asphalt Binder Study
This project will involve physical and chemical analysis of asphalt binders, physical and chemical analysis of crumb rubber modifier (CRM), and correlations between this information and the rheological properties of rubber-modified (R-M) asphalt binders. The following tests would be performed:
  1. SHRP method analysis of asphalt binder
  2. Moisture content of CRM
  3. Ash content of CRM
  4. Carbon black content of CRM
  5. Sulfur content of CRM
  6. Gas Chromatography with Mass Spectroscopy
  7. Infrared Spectroscopy
  8. Differential Scanning Calorimetry
  9. X-Ray Differential Spectroscopy
  10. And more…

Contaminant Sorption of Scrap Tire Rubber Study
This project will include research to lay the groundwork for applications utilizing scrap tire rubber as a contaminant sorption media. The results of this study will provide guidelines regarding what types of scrap tire rubber have the capacity to absorb different contaminants that commonly lead to NPS pollution. The methods to measure such properties will also be refined to such applications. The scope of the project will include:
  1. Development of a new procedure, or adoption of an existing procedure to practically evaluate the effectiveness of scrap tire rubber as a sorption media for a broad range of typical contaminants present in soil, sediment, groundwater, and stormwater runoff (e.g., volatile organic compounds, metals, PCBs, etc.). The primary measure of sorption effectiveness will be the partitioning coefficient of the sorbent (scrap tire rubber).
  2. Establishment of the sorption behavior and capabilities of scrap tire rubber based on the following:
    • Rubber particle size (various sizes of chip & crumb)
    • Rubber type (passenger vs. truck tire)
    • Crumb rubber processing method (ambient vs. cryogenic grinding)
    • Contaminant type (e.g., VOCs, metals, PCBs, etc.)

Cryogenic Rubber-Modified Asphalt Field Test Sections
This project will involve the placement of the first sections of cryogenic rubber-modified hot mix asphalt (R-M HMA) in South Carolina. The test sections will include several roads surrounding Clemson Memorial Stadium (Death Valley), the access road for the Clemson Hydraulics Laboratory, and the driveway and parking area for the new laboratory addition to be constructed at the ARTS facility. Approximately 2,100 tons of cryogenic R-M surface course, 600 tons of cryogenic R-M intermediate course, and 150 tons of cryogenic R-M open-graded friction course will be utilized.

Laboratory Performance of Rubber-Modified Hot Mix Asphalt (R-M HMA) Study
This project is the next logical step to follow research on the high-temperature and low-temperature properties of rubber-modified binders. It will involve the exploration of the effect of several different variables on several different mix performance properties of hot mix asphalt (HMA) made with rubber-modified (R-M) asphalt binders. Several different binder and aggregate sources will be used in the study, as well as the same variables that were used in the high- and low-temperature properties studies:
  1. Crumb rubber processing method (cryogenic vs. ambient)
  2. Type of crumb rubber (truck tire vs. passenger car tire)
  3. Amount of crumb rubber
  4. Size of crumb rubber

Some of the mixture performance properties that will be tested include:

  1. Rut resistance
  2. Fatigue resistance
  3. Moisture susceptibility
  4. Modulus of resilience

Laboratory Performance of Warm Asphalt Mixtures Made with CRM Binders
The main objective of the research project is to investigate the performance of warm mix asphalt as compared to hot mix asphalt. The specific objectives of the research project include the following.
• To study the performance of warm mix asphalt with respect to hot    mix asphalt in terms of indirect tensile strength, rutting and resilient    modulus.
• To study the rheological properties of the warm asphalt binder.
• To study the compatibility of warm asphalt technologies with rubber    modified asphalt binder.
• To study the compatibility of the warm asphalt technologies with    recycled asphalt pavement materials.
• To develop a systematic standard specification for the use of warm    asphalt.

Low-Temperature Properties of Crumb Rubber Modified (CRM) Asphalt Binder Study
This project is the next logical step to follow the research completed by ARTS in 2003 on the high-temperature properties of rubber-modified binders. It will involve the exploration of the effect of several different variables on the low-temperature properties of crumb rubber-modified asphalt binder. Several different binder sources will be used in the study, as well as the same variables that were used in the high-temperature properties study:
  1. Crumb rubber processing method (cryogenic vs. ambient)
  2. Type of crumb rubber (truck tire vs. passenger car tire)
  3. Amount of crumb rubber
  4. Size of crumb rubber

Rubber-Modified Asphalt Research
This project will involve the completion of several research projects involving rubber-modified binder, rubber-modified open-graded friction course, stress absorbing membrane interlayer, and reclaimed asphalt pavement in rubber-modified mixtures. These projects were grouped together because the results from much of the required testing can be used for several of the projects. The projects will cover the following topics:
  1. Examination of aging (or anti-aging) effects caused by interaction of CRM with the asphalt binder in CRM binder.
  2. Developing high quality CRM binder to be used for OGFC and drainage mixtures by enhancing binder properties with different combinations of passenger car tire and truck tire rubber to modify the binder, and by using chemical- and crumb rubber- modified binder.
  3. Examining the stress-absorption properties of CRM binder used as a SAMI, such as the stress-strain relationship and the influence of CRM type, CRM percentage, and asphalt binder source on the stress absorption properties.
  4. Investigation of the resilient modulus of recycled mixtures using CRM binders.
  5. Evaluation of the durability of the porous mixtures using high quality CRM binder through strength testing, rutting resistance testing, and Cantbra testing (abrasion test).

Septic Tank Tire Chip Study
1. Several different tire chip sizes will be tested:
   a. 6-inch
   b. 4-inch
   c. 2-inch
   d. 0.5-inch

2. Leachate from the tire chip drainage layers will be measured under the following test conditions:
   a. In distilled and deionized water at pH 2, 6, 8 and 12,
   b. In a typical rain water
   c. In a typical hard and soft groundwater
   d. In TCLP test conditions

3. The hydraulic conductivity of the tire chip drainage layers will be measured.


Sound Absorption of Rubber-Modified Asphalt Study
The use of crumb rubber modified (CRM) asphalt mixtures have been identified as having the ability to reduce the noise from the tire/pavement interface. However, there has been limited research comparing the sound absorbing benefits of CRM asphalt to the same mixtures produced with conventional binders. Results of this study have the potential to add to the attractiveness of CRM asphalt as a paving material, which has already shown to be a more durable paving material. The scope of the project will include:
  1. Conduct mix designs using CRM binders and the conventional alternatives (e.g., PG 64-22 or SBS modified PG 76-22) combined with aggregates from three different sources for the following mix design types (18 mix designs):
    1. 9.5 mm surface course
    2. 12.5 mm surface course
    3. 12.5 mm open graded friction course (OGFC)
  2. Measure the sound absorbance of the above mixtures using laboratory methods.
  3. Measure the following properties of the mixtures listed in Item 1 that potentially effect the sound absorption:
    1. Permeability
    2. Surface texture

 Contact Us    |    Related Links    |    Directions       

2002 HUGO DRIVE • CLEMSON UNIVERSITY • CLEMSON, SC 29634
PHONE: (864) 656-6799 • FAX: (864) 656-6186 • EMAIL: arts@ces.clemson.edu