Download Free Resilient Modulus And Fatigue Life Characterization Of Asphalt Concrete Mixtures Used In The Ohio Test Road Book in PDF and EPUB Free Download. You can read online Resilient Modulus And Fatigue Life Characterization Of Asphalt Concrete Mixtures Used In The Ohio Test Road and write the review.

This research study aimed to determine the dynamic modulus, bending stiffness and fatigue properties of four representative Superpave Hot Mix Asphalt (HMA) mixtures used in the construction of base layers of Kansas flexible pavements and to compare the measured values with those predicted by the National Cooperative Highway Research Program (NCHRP) Design Guide. To achieve these objectives, asphalt concrete beams were tested in third point-bending at constant strain, at four temperatures and four levels of strain. Dynamic resilient modulus tests were performed on asphalt cylindrical specimens at five temperatures and five loading frequencies. Multi-linear regression analysis was performed to develop a linear relationship between the bending stiffness and the fatigue life for the asphalt mixes tested.
It is often desirable to be able to obtain a comprehensive characterization of the performance-related properties of asphalt concrete with as few tests as possible. The New Mexico State Highway and Transportation Department is interested in obtaining a comprehensive characterization of the performance-related properties of the four types of asphalt concrete mixtures that are commonly used in the state. These properties include: the strength, the resilient modulus, the rutting characteristics, and the fatigue/cracking characteristics. Typically, different tests are needed to determine these characteristics. However, the approach taken here to obtain the desired information is through dynamic testing with large (15 cm diameter x 30 cm high) cylindrical asphalt concrete specimens at four different load levels, frequencies, and temperatures. The load applied were 1112 N, 2224 N, 4448 N, and 8896 N; at frequencies of 1 Hz, 4 Hz, 8 Hz, and 16 Hz. Test temperatures were 4.4°C, 25°C, 37.8°C, and 60°C. Continuous haversine load cycles were applied for each test set and the response to the repeated loadings were recorded. Resilient modulus histories were obtained. Rutting characteristics of the material at different temperatures were obtained from the residual deformation histories. The thermal viscoelastic properties were determined from the deformation response at the different temperatures. The change in the damping characteristics with repeated loading were determined through analysis of the data in the frequency domain. Since damping properties can be related to the embrittlement and aging characteristics of materials, the fatigue properties were also inferred. Additionally, it is shown that the degree of susceptibility of the asphalt concrete to cracking and reflection cracking can also be estimated.
The objective of this study was to determine the fundamental resilient moduli (Mr) parameters of four asphalt-rubber gap-graded (AR-gap), one asphalt-rubber open-graded (AR-open), four polymer-modified gap-graded (P-gap), and two conventional dense-graded asphalt concrete (DGAC) mixes at various temperatures and frequencies using ASTM D7369-11-based standard resilient modulus test [Standard Test Method for Determining the Resilient Modulus of Bituminous Mixtures by Indirect Tension Test, ASTM International, West Conshohocken, PA, 2011, www.astm.org]. Mr tests were conducted at 15°C, 25°C, and 35°C and at 0.5, 1, 1.5, and 2 Hz on a total of 33 samples with three samples per mix. DGAC mixes had the highest Mr followed by P-gap and AR-gap, and then followed by the AR-open mixes. Mr master curves were constructed for the mixes with 25°C as a reference. Furthermore, the Mr model was developed based on the material properties of 11 mixes totaling 121 data points provided by R2adj = 0.9436 (adjusted coefficient of estimation), and Se/Sy = 0.1579 (ratio of standard error to standard deviation indicative of relative accuracy of the predictive model), depicting excellent correlation between the measured and predicted Mr. Fatigue lives of each mix type was predicted using the obtained Mr and estimated tensile strains. The fatigue lives of the modified gap-graded mixes were found to be seven times higher than the conventional mixes. A novel approach was also devised to obtain fatigue lives of conventional and modified mixtures with a reduced thickness design concept based criterion with Mr being the major input parameter. Overall, it is envisioned that the Mr parameters obtained in this study will be helpful to understand the performance characteristics of the different mixes through future laboratory-field correlations.
Over the past decade, the Texas Department of Transportation (TxDOT) focused research efforts on improving mixture design to preclude rutting in the early life of the pavement, which also offered increased resistance to moisture damage, but fatigue cracking may surface in the long term particularly if the binder stiffens excessively due to aging. The primary goal of this project is to evaluate and recommend a fatigue analysis system for TxDOT designs to ensure adequate mixture fatigue performance in a particular pavement structure under specific environmental and loading conditions. A secondary goal of comparing fatigue resistance of commonly used TxDOT mixtures including investigating the effects of aging will also be realized.
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.