Browsing by Subject "Superpave"

Now showing 1 - 4 of 4
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    Development of Superpave 5 Asphalt Mix Designs for Minnesota Pavements
    (Minnesota Department of Transportation, 2022-06) Yan, Tianhao; Marasteanu, Mihai; Le, Jia-Liang; Turos, Mugurel; Cash, Kristen
    High field density is desired for improving the durability of asphalt pavements. This research aims to develop Superpave 5 mixtures (more compactable than traditional Superpave mixtures) by using locally available materials to improve the field density in Minnesota. First, previous projects in Minnesota were investigated. The mean and standard deviation of field density in Minnesota were about 93.5% Gmm and 1.5% Gmm, respectively. Significant correlations were identified between field density and mix design indices, i.e., Ndesign, NMAS, and fine aggregate angularity (FAA). Four traditional Superpave mixtures were then selected and modified to Superpave 5 mixtures by adjusting their aggregate gradations while maintaining the asphalt binder content. Laboratory performance tests were performed to check the mechanical properties of the modified mixtures. The results showed it was feasible to design Superpave 5 mixtures (more compactable mixtures) by adjusting aggregate gradations, and the improved compactability of the mixtures did not adversely affect the performance of the mixtures for rutting, stiffness, and cracking resistance. Therefore, Superpave 5 mixtures can increase field density as well as other performances of asphalt pavements if implemented.
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    Experimental and Computational Investigations of High-Density Asphalt Mixtures
    (Minnesota Department of Transportation, 2019-10) Marasteanu, Mihai; Le, Jia-Liang; Hill, Kimberly; Yan, Tianhao; Man, Teng; Turos, Mugurel; Barman, Manik; Arepalli, Uma Maheswar; Munch, Jared
    Compaction of asphalt mixtures represents a critical step in the construction process that significantly affects the performance and durability of asphalt pavements. In this research effort, the compaction process of asphalt mixtures was investigated using a combined experimental and computational approach. The primary goal was to understand the main factors responsible for achieving good density and was triggered by the success of a recently proposed Superpave 5 mix design method. First, a two-scale discrete element method (DEM) model was developed to simulate the compaction process of asphalt mixtures. The computational model was anchored by a fluid dynamics-discrete element model, which is capable of capturing the motion of aggregates in the viscous binder. The model was then calibrated and validated by a series of experiments, which included rheological tests of the binder and a compaction test of the mixture. It was concluded that the compaction process was significantly influenced by the rheological properties of the fine aggregate matrix and by the sphericity of the coarse aggregates. Finally, the mechanical properties of two high-density mixtures were determined and compared with mechanical properties of mixtures used for MnROAD 2017 National road Research Alliance (NRRA) test sections. It was found that the properties of high-density mixtures as a group were not significantly different compared to the properties of conventional mixtures.
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    Improvement of Asphalt Mixture Design for Cold Climatic Region
    (2024-02) Manickavasagan, Vishruth
    Asphalt material is widely used for roadways in the United States, underscoring its crucial role in the country's transportation infrastructure. In cold climatic regions such as Minnesota, the asphalt pavement undergoes significantly low-temperature cycles in winter resulting in shrinkage of the asphalt, which leads to thermal cracking, and subsequently potholes. The present study explores the behavior of asphalt mixes with an emphasis on improving the resistance of the mixes against low-temperature thermal cracking. The study included high and low-density mixes and considered the impact of polymer-modified asphalt binders. In the first phase of the study, seven asphalt mixes were designed and tested, with three using the conventional Superpave (Superpave-4) mix design method, three utilizing the Superpave-5 mix design method for high-density asphalt mixes and one using regressed air-void method for a reference. In the second phase, eight asphalt mixes were tested, with four using polymer-modified binder and four using non-polymer-modified binder. The Disc-Shaped Compact Tension (DCT) test, Indirect Tensile Strength (ITS), and Dynamic Modulus (DM) tests were conducted to study the performance of the mixtures. From the test results, it was found that the Superpave-5 mix design samples containing polymer-modified binders exhibited better fracture properties or higher resistance to low-temperature thermal cracking compared to the Superpave-4 mixes, with non-polymer modified binder. The study further explores other relevant behaviors of Superpave-4 and Superpave-5 mixes to recommend needed modifications of the asphalt mixes that will experience less environmentally driven distresses when used in cold climatic regions.
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    Optimizing Asphalt Mixtures for Low-volume Roads in Minnesota
    (Minnesota Department of Transportation, 2023-08) Barman, Manik; Dhasmana, Heena; Manickavasagan, Vishruthi; Marasteanu, Mihai
    Minnesota has a large number of low-volume asphalt roads. These roads typically fail because of environmental factors, such as frigid temperatures, freeze-thaw cycles, and seasonal and daily temperature variations. The goal of this study was to suggest modifications to asphalt mixture designs currently used for low-volume roads in Minnesota to improve the resistance of the mixes against the environmentally driven distresses. The study was conducted by accomplishing multiple tasks, such as a literature review, online survey, fieldwork studying the cause of the asphalt pavement distresses, laboratory work comparing asphalt mixtures designed with Superpave-4, Superpave-5, and regressed air voids methods, and studying the field compaction of Superpave-5 mixes. The mechanical performance of the asphalt mixes was studied by conducting Disc-Shaped Compact Tension (DCT), Indirect Tensile Strength (ITS), and Dynamic Modulus (DM) tests. The study included both laboratory- and plant-produced mixes. The study found that asphalt layers for the low-volume roads did not get enough densification, which augments environmentally driven distresses, such as thermal cracks, and longitudinal joint cracks. The Superpave-5 method holds considerable promise for the design of asphalt mixtures for low-volume roads in Minnesota, which may likely increase the asphalt layer densification and mitigate some of the common distresses.