Guidelines for Utilization of Field Sands in Superpave Mixtures of Texas

Details

• Creators:
  Vaid, Suhail R ; Afsha, Sharmila ; Montoya, Miguel A. ; Walubita, Lubinda F. ; Abdallah, Imad N. ; Nazarian, Soheil
• Corporate Creators:
  University of Texas at El Paso. Center for Transportation Infrastructure Systems ; Texas A&M Transportation Institute
• Contributors:
  Patton,Travis ; Alvarez, Christopher ; Peters, Lacy ; Rangel, Maribel ; Ruiz, Monica
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office
• Subject/TRT Terms:
  Admixtures Asphalt Binder Asphalt Concrete Mixture Asphalt Concrete Pavements Binder Content Formaldehyde Guidelines Methylene Blue Value Rutting Sand Sand Equivalent Stripping (Pavements) Superpave

  More +
• Publication/ Report Number:
  FHWA/TX-25/0-7111-1 ; TX 0-7111
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas ; United States
• Corporate Publisher:
  University of Texas at El Paso. Center for Transportation Infrastructure Systems ; Texas Transportation Institute. Texas A&M University
• Abstract:
  Field sands have been used in hot mix asphalt (HMA) pavements to improve workability since they are readily available and less expensive than crushed materials. However, due to their potential adverse effects on performance, field sands are typically limited to 10% of the aggregates. A key issue is the presence of harmful clay particles that can significantly impact asphalt concrete (AC) performance. This study investigated the effects of clay minerals on AC performance, focusing on Superpave mixtures and evaluating their clay and sand effects. Clay properties were assessed using the methylene blue value (MBV) and sand properties using the sand equivalent (SE) test. The Hamburg wheel tracking test (HWTT) was used for evaluating rutting and stripping properties of the mixtures. Superpave gradation C, twenty-four field sand sources, two binder grades (PG 64-22 and PG 70-22), and hydrated lime were used for this study. The maximum and minimum values of the MBV for the field sands were 45.8 mg/g and 3.7 mg/g, respectively. For the aggregate blend, the maximum MBV was 10 mg/g, and the minimum MBV observed was 2.4 mg/g. The field sands had SE values in the range of 37 to 98 whilst the mixtures evaluated had an SE in the range of 50 to 91 when quantified on the aggregate blend. For PG 64-22, an MBV of less than 4 mg/g indicated excellent performance, while for PG 70-22, an MBV of less than 8 mg/g was optimal. These findings were consistent across field sand percentages of 5%, 10%, and 20% (by weight of the total aggregates) that were investigated. Results also showed that the use of a higher binder grade and hydrated lime increases the stripping resistance of the asphalt mixtures incorporating field sands. New guidelines are recommended for implementing a method that incorporates field sands into Superpave mixtures without compromising performance.
• Format:
  PDF
• Funding:
  0-7111
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:2efd23fd14d1131611fba85dab88ebcb9b920299f9a0251fa53e0af6f66da1bffde1e6d0356b54092565bb0ecc8d13b87c7c9c50fc1933c995ce17d11421a204
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/80059/dot_80059_DS1.pdf
• File Type:
  [PDF - 1.91 MB ]