A simple test procedure for evaluating low temperature crack resistance of asphalt concrete.

Details

• Creators:
  Kim, Sang-Soo ; Sargand, Shad ; Wargo, Andrew
• Corporate Creators:
  Ohio University. Ohio Research Institute for Transportation and the Environment (ORITE)
• Corporate Contributors:
  Ohio. Dept. of Transportation. Office of Research and Development ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Cracking of asphalt concrete pavements
  • Low temperature tests Pavements, Asphalt concrete--Cracking--Ohio
  • Pavements, Asphalt concrete--Ohio--Testing
• Publication/ Report Number:
  FHWA/OH-2009/5
• Resource Type:
  Tech Report
• Geographical Coverage:
  Ohio
• Edition:
  Final report.
• Corporate Publisher:
  Ohio Research Institute for Transportation and the Environment
• Abstract:
  The current means of evaluating the low temperature cracking resistance of HMA relies on extensive test ; methods that require assumptions about material behaviors and the use of complicated loading equipment. The purpose ; of this study was to develop and validate a simple test method to directly measure the cracking resistance of hot mix ; asphalt under field-like conditions. ; A ring shape asphalt concrete cracking device (ACCD) was developed. ACCD utilizes the low thermal ; expansion coefficient of Invar steel to induce tensile stresses in a HMA sample as temperature is lowered. The results of ; the tests of the notched ring shaped specimens compacted around an ACCD Invar ring showed good repeatability with ; less than 1.0°C (1.8°F) standard deviation in cracking temperature. A laboratory validation indicated that ACCD results ; of five mixes correlate well with thermal stress restrained specimen test (TSRST) results with the coefficient of ; determination , r2 = 0.86. To prepare a sample and complete TSRST measurement, it takes minimum 2-3 days. For ; ACCD, two samples can be easily prepared and tested in a single day with a small test set-up. The capacity of ACCD ; can be increased easily with minimal cost to accommodate a larger number of samples. ; Among factors affecting the low temperature performance of HMA, the coefficient of thermal expansion (CTE) ; of aggregate has been overlooked for years. A composite model of HMA is proposed to describe the low temperature ; cracking phenomenon. Due to the orthotropic and composite nature of asphalt pavement contraction during cooling, the ; effects of aggregate CTE is amplified up to 18 times for a typical HMA. Of 14 Ohio aggregates studied, the maximum ; and the minimum CTEs are 11.4 and 4.0 x 10-6/°C, respectively. During cooling, the contraction of Ohio aggregate with ; high CTE can double the thermal strain of asphalt binders in the asphalt mix and may cause asphalt pavement thermal ; cracking at warmer temperature.
  More +
• Format:
  PDF
• Funding:
  134260
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17206/dot_17206_DS1.pdf
• File Type:
  [PDF - 4.00 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:0c5c8149201ca8df4816822aa878248ce7ac713349b70b49006cf169f13cd646f284407a0f77913088b58acdf45f8dd5ad44ea94ec797038470634a476fcecb9