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In this study, the fatigue resistance of different asphalt mixture types subjected to the same aging condition was evaluated using linear viscoelastic properties of asphalt mixtures. The relaxation spectra were determined from the dynamic modulus test based on the linear viscoelastic theory, and the relationship between the parameters of relaxation spectra and the parameters of the storage modulus master-curves were developed. The Texas overlay test was conducted to evaluate the fatigue resistance with the number of load cycle to failure used as the measure of fatigue resistance. From the corresponding results, it is shown that the inflection point frequency of the dynamic modulus master-curves could be used to assess the fatigue resistance compared to other parameters. The Glover-Rowe parameter also exhibited a fair relationship with the fatigue resistance of the asphalt mixtures. The effect of the shape parameter (γ) of the dynamic modulus master-curves was quantified but seemed not very sensitive to fatigue resistance for the asphalt mixtures evaluated. In the study, a new parameter (VECIndex) was developed to evaluate the fatigue resistance, which considered the inflection point frequency and shape of the dynamic modulus master-curves, both of which influence the linear viscoelastic properties and fatigue resistance of asphalt mixtures. [ABSTRACT FROM AUTHOR]

• Rutting Lab Test Comparisons – Practicality, Simplicity, and Repeatability. • Correlation of lab results with Field Rutting Performance. • Rutting Prediction Potential and Field Correlations. • HMA Screening Criteria using different Rutting Lab Test. Rutting or permanent deformation (PD) is one of the most critical distresses occurring in hot-mix asphalt (HMA) pavements. However, despite all of the recent efforts aimed at producing new test methods and better road materials, HMA rutting is still prevalent, particularly in hot regions and/or on highways with heavy truck-traffic loading. Laboratory testing to screen HMA mixes against rutting during the HMA mix-design stage thus constitute a vital step towards optimizing field performance. In this Texas case study, five laboratory test methods were comparatively evaluated for quantifying and screening four HMA mixes' rutting resistance potential relative to their field performance on in-service highway test sections under conventional traffic loading and climatic conditions. The five test methods included the dynamic modulus (DM), flow number (FN), repeated load permanent deformation (RLPD), simple punching shear test (SPST), and Hamburg wheel tracking tester (HWTT), respectively. The four HMA mixes evaluated included commonly used Texas fine-, coarse-, and porous-graded mixes. The data for the study, both laboratory and field performance including climate (temperatures) and traffic loading, were all extracted from Texas flexible pavements and overlays database, namely the Texas Data Storage System denoted as the DSS. Overall, all the laboratory test predictions correlated well with the actual measured field performance data, with the HWTT and SPST tests exhibiting superiority over the other test methods. As theoretically expected, the coarse-graded HMA mix out-performed the other mixes, with the fine- and porous-graded mixes being at the lower end of the spectrum. [ABSTRACT FROM AUTHOR]

The first section of this paper summarizes the efforts of Texas Department of Transportation (TxDOT) to evaluate the coefficients of thermal expansion (COTEs) of a total of 93 concrete mixtures, of which the only difference is the coarse aggregate incorporated. The mean COTE value of siliceous gravel concrete is about 30% higher than that of limestone concrete. The data in Texas shows that the upper 50% COTE values of limestone concrete overlaps the lower 20% COTE values of siliceous gravel concrete. The results strongly suggest that pre-qualification of coarse aggregate for typical paving concrete in aspect to COTE should be considered. A model by Emanuel and Hulsey is used to back calculate COTE of coarse aggregate. The second section of this article compares the COTE data set on existing pavement measured by Federal Highway Administration with those obtained at TxDOT concrete laboratory. [ABSTRACT FROM AUTHOR]