Published Online: 16 November 2007
Page Count: 10
Former Graduate Student, Penn State University, current Project Manager of the Transtec Group Inc., Austin, TX
Director, the Northeastern Center of Excellence for Pavement Technology (NECEPT), Penn State University, PA
(Received 30 January 2007; accepted 26 September 2007)
Thermal expansion and contraction (TE/TC) of asphalt concrete (AC) play a significant role in both the thermal fatigue and low-temperature cracking of AC pavements. This paper discusses a test method and procedure developed to determine the AC coefficients of thermal expansion and contraction (CTE and CTC, respectively). Cylindrical specimens were subjected to temperature variations in an environmental chamber and specimen deformations were measured using extensometers. Temperature was applied in the range of −5°C to 40°C during both expansion and contraction phases. A specimen made from ceramic with very low CTE/CTC was also tested so that the influence of the self TE/TC of extensometers could be accounted for, and therefore, the measured deformation of an AC specimen was properly adjusted. A finite element (FE) model was developed to simulate the thermal stresses and strains inside the specimen, and to provide means for reliable computation of CTE/CTC. For this FE model, required AC viscoelastic properties were determined from the dynamic modulus test. The CTE/CTC of AC were then determined by using the calibrated deformation-temperature relationship. The standard aluminum and rubber specimens were also tested for TE/TC within a temperature range to validate the developed test method and computation approach. It was found that the CTE/CTC of AC were nonlinear and temperature dependent. The CTE/CTC determined for the aluminum and rubber specimens were found to be close to the standard values, therefore, validating the proposed approach for determination of CTE/CTC of AC.
Paper ID: JTE101024