Development of a semicircular bend (SCB) test method for performance testing of Nebraska asphalt mixtures.

Details

• Creators:
  Nsengiyumva, Gabriel ; Kim, Yong-Rak ; You, Taesun
• Corporate Creators:
  University of Nebraska--Lincoln. Dept. of Civil Engineering
• Corporate Contributors:
  Nebraska. Dept. of Roads ; United States. Federal Highway Administration ; United States. Department of Transportation. Federal Transit Administration ; United States. Department of Transportation. Research and Innovative Technology Administration
• Subject/TRT Terms:
  Analysis Of Variance Asphalt Concrete Pavements Asphalt Mixtures Bend Tests Fracture Mechanics Statistical Analysis Test Procedures
• Publication/ Report Number:
  SPR-P1(15) MPMC07
• Resource Type:
  Tech Report
• Geographical Coverage:
  Nebraska
• Corporate Publisher:
  Mid-America Transportation Center
• Abstract:
  Granted that most distresses in asphalt (flexible) concrete (AC) pavements are directly related to fracture, it becomes clear
  
  that identifying and characterizing fracture properties of AC mixtures is a critical step towards a better pavement design.
  
  This report examines the testing variables of a reliable and practical semicircular bending (SCB) test for evaluating the
  
  fracture characteristics of asphalt concrete mixtures at intermediate service temperature conditions. The first part of this
  
  report investigates the repeatability of the SCB fracture test method by integrating a statistical-experimental approach to
  
  identify testing variables of the SCB test that result in repeatable test results. Toward this end, five testing variables (the
  
  number of testing specimens, specimen thickness, notch length, loading rate, and testing temperature) of the SCB test were
  
  investigated due to their significant effects on mixture fracture characteristics. After statistical analysis of 18 specimens
  
  tested with a typical testing variables, approximately, five to six specimens/replicates were found to be a reasonable sample
  
  size that could properly represent asphalt concrete fracture behavior using the SCB test method. The coefficient of variation
  
  (COV) of the mixture fracture energy was used to evaluate the effect of each variable on the repeatability of test results. A
  
  range of 1 mm/min. to 5 mm/min. for the loading rate, a notch length from 5 mm to 25 mm, and a specimen thickness of
  
  40 mm to 60 mm and a testing temperature of 15-40°C showed a good repeatability of fracture energy with small COVs
  
  (≤15 %). The second part of this work is to investigate the sensitivity of the SCB test using the previously determined
  
  testing variables. Fourteen different asphalt concrete (AC) mixtures collected from 12 field construction projects in
  
  Nebraska were used in this task. The ANOVA test showed statistically significant differences between mixtures at a 95%
  
  confidence level. Tukey’s HSD multiple-comparison analysis found similarities within mixtures of same types and
  
  differences between mixture types. In addition, the fracture energy of bituminous mixtures increased with increasing amount
  
  of virgin asphalt content in mixture. Overall, the SCB test method developed herein proved to be repeatable and sensitive
  
  to changes in mixtures, and thus a promising tool for evaluating the fatigue fracture resistance of AC mixtures.
  
  
• Format:
  PDF
• Funding:
  26-1121-4023-001
• Collection(s):
  University Transportation Centers US Transportation Collection
• Main Document Checksum:
  urn:sha-512:d9e412817ccd3078b53a3144fe38aae8c69a5a8a1a73859a14c62e8685f974ac1bcd97853f8c792c56b52eb04058b7b77f510cefa529e2fa9554d6a888f02c4e
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29737/dot_29737_DS1.pdf
• File Type:
  [PDF - 9.16 MB ]