1. Assessment of asphalt binder content, temperature and loading rate in indirect tensile strength and resilient modulus tests of a hot-mix asphalt – Comparison with Marshall design method.
- Author
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Bastidas-Martínez, Juan Gabriel and Rondón-Quintana, Hugo Alexander
- Subjects
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ASPHALT testing , *TENSILE strength , *ASPHALT , *FATIGUE cracks , *PEAK load , *TEMPERATE climate - Abstract
The optimum asphalt content (OAC) in a hot-mix asphalt (HMA) is an important parameter that affects pavement performance and durability. To obtain it, it is essential to consider variables associated with the action of the climate and the rate of load application. The traditional way of obtaining the OAC through the Marshall test does not consider these variables. Additionally, this test is more appropriate to evaluate the performance of HMAs in high-temperature climates (mainly to evaluate rutting resistance) and does not consider the types of distresses that predominate in temperate and/or cold climates (e.g., fatigue cracking). This study analyzed the influence of asphalt binder content on the performance of an HMA by performing indirect tensile strength (ITS) and resilient modulus (RM) tests, considering temperatures of 10, 20, and 40 ºC, with load application rates of 10, 30 and 50 mm/min for the ITS test, and loading frequencies of 2.5, 5.0 and 10.0 Hz for the RM test. From the ITS test, the peak load (P), the slope at the inflection point (m), the stiffness (St), and the work of fracture (Wf) were obtained. The performance of the HMA based on these parameters was evaluated and an OAC was defined and compared with that obtained traditionally by the Marshall test. Additionally, these values were compared with the results obtained from resilient modulus (RM) tests. A mathematical correlation between the ITS and RM tests was reported. Temperature, speed of load application in the ITS test, and frequency of load in the RM test affected the performance of the HMA. P, ITS, St, Wf, and RM increased when temperature decreased and loading speed or frequency increased. The opposite was true for parameter m. For the HMA evaluated in the present study, the results show that the OAC obtained from ITS and RM tests is 0.5% higher than that obtained from the Marshall test. In other words, HMA design methods should include ITS and RM tests to help reduce susceptibility to cracking in temperate climates and rutting in high-temperature climates. It's suggested to conduct similar studies using different aggregates, asphalts, and gradations. • The effect of asphalt binder content, temperature, and loading rate on an HMA was studied by ITS and RM tests. • The fracture properties of an HMA were evaluated in the ITS test. • The OAC obtained from the Marshall test differs from the ITS and RM tests. • There is a mathematical correlation between the results of the ITS and RM tests. • For temperate climates, the design of HMAs is recommended by performing Marshall, ITS, and RM tests together. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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