Browsing by Subject "Asphalt"
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Item Asphalt Mixture and Binder Fracture Testing for 2008 MnROAD Construction(Minnesota Department of Transportation, 2009-12) Marasteanu, Mihai; Moon, Ki Hoon; Turos, MugurelThis report summarizes the results of an experimental effort to characterize the low-temperature behavior of asphalt mixtures and binders from the recently reconstructed cells at the MnROAD facility. In depth analysis of the data was not part of this study; this will be accomplished in several concurrent research projects.Item Comparison of thermal stress calculated from asphalt binder mixture creep compliance data(2010-08) Moon, Ki HoonLow temperature cracking represents a significant problem in asphalt pavements built in Northern US and Canada. As temperature decreases rapidly, thermal stresses develop in the restrained surface layer and, when the temperature reaches a critical temperature, cracking occurs. In this thesis, statical analyses were used to compare thermal stresses that develop in an idealized asphalt pavement layer calculated from experimental data obtained with three different test methods: 1) Asphalt mixture creep test using Bending Beam Rheometer (BBR) 2) Asphalt mixture testing using Indirect Tensile Test (IDT) 3) Asphalt binder creep test using BBR and an empirical Pavement Constant Thermal stresses calculated using mixture BBR and mixture IDT data were reasonably identical. Thermal stresses calculated using binder BBR data and an empirical Pavement Constant were significantly different than the other calculated thermal stresses. The effect of physical hardening on thermal stress evaluation was investigated for a limited number of materials and it was found that this effect significantly affect thermal stress magnitude.Item Cracking Performance Evaluation of Minnesota Asphalt Pavements(2016-02) Hoplin, ChelseaThermal cracking is the most prevalent distress for asphalt roadways in Minnesota. The cracks form pathways for water to permeate into the pavement structure degrading its integrity and shortening the life span. This thesis investigates asphalt mixture design parameters and laboratory tests measures of 25 pavement sections on 18 highways in Minnesota to draw conclusions on how these parameters relate to transverse cracking performance. The results showed that the coarse gradation of asphalt mixes currently being used by MnDOT typically have higher permeability rates than the typical range for dense graded asphalt mixtures, which makes these pavement sections more susceptible to moisture-induced damage. Next, this study analyzed the transverse and longitudinal field cracking performance of 295 pavement sections on 28 highways with respect to their asphalt binder type and polymer modification. The effect of asphalt binder type and modification was compared to field cracking performance in relation to construction type, asphalt binder supplier, and dynamic shear rheometer parameters: phase angle and dynamic shear modulus. The polymer-modified PG58-34 binder performed better than the non-polymer modified version. The last part of this thesis evaluated the sensitivity of flexible pavement thermal cracking performance to variations in disk-shaped compact tension (DCT) fracture energy. This study included nearly 200 simulations representing combinations of 3 climates, 3 asphalt thicknesses, 3 asphalt mixtures and 6 fracture energy levels. The motivation of this work was to investigate the sensitivity to the 400 J/m2 threshold that is being used in the implementation of the DCT performance test specification. It is concluded from this study that variation of 25 J/m2 is enough to show a difference in cracking performance.Item 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, KristenHigh 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.Item Impact of asphalt mixture design parameters on transverse cracking performance and laboratory testing results(2015-04) Helmer, Benjamin WilliamIn cold climate regions, thermal cracking of asphalt pavements is a primary pavement distress. Cold climates cause thermal contraction within the pavement. When combined with the brittle behavior of asphalt at low temperatures, the thermally induced stresses are relieved by transverse cracks forming in the pavement. This cracking facilitates poor ride quality and premature failure of the pavement. There is currently no asphalt mixture performance test required by a majority of Department of Transportations (DOTs) in the United States to address the issue of thermal cracking. Previous research has indicated that fracture energy of asphalt mixtures is a reliable predictor of transverse cracking performance. This mechanistic property of asphalt mixtures can be found using the disk-shaped compact tension (DCT) test. On basis of previous research, a low-temperature cracking performance specification that uses DCT fracture energy has been developed. This project focused on eighteen highways containing twenty-six separate study sections. The projects encompassed different construction techniques, material compositions and climatic zones. The results from field studies, analysis of the mix parameters for each section and laboratory testing for sections are presented in this document. The results provide validation for previous research that suggests the use a performance test is vital to accurate projection of roadway transverse cracking performance. Other findings include reaffirmation of common knowledge about various mix parameters that suggest increasing or decreasing values will have positive and negative effects on both cracking amounts and performance testing. In nearly all instances, sections with an overlay construction type performed inferior to reclaimed construction types. For example, reclaimed sections exhibited roughly one-third the average transverse cracking amount of overlay sections. This phenomenon will be monitored in future studies.Item Improvement of Asphalt Mixture Design for Cold Climatic Region(2024-02) Manickavasagan, VishruthAsphalt 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.Item Investigation of Performance Requirements of Stabilized Full-Depth Reclamation(2016-05) Milavitz, RoseStabilized full-depth reclamation (SFDR) is a pavement rehabilitation method in which distressed asphalt is mixed with a stabilizer to form a base for new asphalt. SFDR has been used in Minnesota but there is a lack of guidelines for its design. This research investigates the relationship between SFDR properties and overall pavement performance, through which the desirable properties of SFDR materials can be determined. Material tests for creep compliance, Poisson’s ratio, tensile strength, dynamic modulus, and fracture energy were performed on SFDR samples from four roadways. The results were used to model the pavements using MEPDG and MnPAVE software. The rutting predictions were compared to the field measurements and parametric analysis was conducted to determine the effect of the dynamic modulus on the lifetime and reliability of the pavement. It was found that MEPDG can accurately predict rutting while MnPAVE is ideal for parametric and reliability analyses of SFDR pavements.Item Investigation of the thermal parameters of reclaimed asphalt materials with applications to asphalt recycling(2014-08) DeDene, Christopher D.Asphalt concrete is the third most widely used resource in the world, next to Portland Cement Concrete and water. In the United States alone, over 550 million tons of hot mix asphalt (HMA) are produced at more than 4,000 asphalt plants across the country. With over 94% of the paved roads in the United States surfaces with asphalt concrete, it's safe to say asphalt pavement is what America drives on. However, a majority of today's pavement projects are geared towards rehabilitation and reconstruction of existing pavements, rather than construction of new roads. While it is true that asphalt pavement is 100% recyclable and it is the most recycled material in America, the reality is most roads contain no more than 20% recycled material. There are many factors that prohibit new road construction in excess of 20% recycled content, and this thesis aims to explore just one of those factors - the thermodynamics of hot mix asphalt pavement recycling. Most research that is investigating the use of high amounts of Reclaimed Asphalt Pavement (RAP) have been based on empirical trials. This work has approached the issue of pavement recycling by measuring the thermal properties of recycled asphalt, examining the thermodynamic limits of asphalt drum mixing, and by modeling asphalt mixing drums using finite element techniques to determine the amount of time required to achieve full melting inside of asphalt drums. It was found that for many different drum configurations, there is insufficient retention time for RAP to reheat. This insufficient heating could cause premature failures in asphalt pavements using high percentages of RAP. A secondary goal of this thesis is to explore the benefits of using the waste mining material, taconite tailings, in new asphalt pavements. This research shows there is thermodynamic benefit gained by using taconite tailings because they can be heated faster than traditional aggregates. This heating supplies more heat to RAP, which in turn, may allow for more of the recycled asphalt pavement to be incorporated into new asphalt pavements.Item New Microsurfacing Specifications Improve Cold-Temperature Performance of Asphalt Pavements(Transportation Engineering and Road Research Alliance (TERRA), 2015-04) Transportation Engineering and Road Research Alliance (TERRA)This 2-page fact sheet provides information about microsurfacing and recent research to enhance its effectiveness in colder climates.Item Performance of Taconite Aggregates in Thin Lift HMA: Final Report - January 31, 2012(University of Minnesota Duluth, 2012) Zanko, Lawrence M; Johnson, Ed; Marasteanu, Mihai; Patelke, Marsha Meinders; Linell, David; Moon, Ki Hoon; Oreskovich, Julie A; Betts, Ray; Nadeau, Lynette; Johanneck, Luke; Turos, Mugur; DeRocher, WillThis project was undertaken to advance the knowledge of the beneficial uses of taconite mining coarse tailings (taconite fine aggregate) for thin lift hot mix asphalt (HMA), to facilitate technical information gathering and marketing of such uses and properties, and to encourage the beneficial use of recycled/byproduct materials like durable and wear- and skid-resistant taconite (Mesabi) aggregates, recycled asphalt pavement (RAP), and asphalt shingles. In combination, the use of each is highly desirable because it promotes resource conservation, safety, and energy-saving. Outcomes of this study suggest that Mesabi rock and tailings products show promise as components of 4.75-mm Dense-graded, Stone Matrix Asphalt, and Ultra-Thin Bonded Wearing asphalt mixtures. Laboratory and field investigations of taconite tailings should continue. The Mesabi rock can be incorporated in standard Superpave, SMA, and fine/sand asphalt mixtures in upcoming construction projects. In each case construction and long term field performance should be evaluated. The investigators conclude that taconite-based thin lift HMA mixes that also incorporate RAP should be recognized as an environmentally sound, i.e., combining the use of byproduct and recycled/reclaimed materials, and high-quality option for HMA pavement rehabilitation and preservation. Collectively, the material testing results suggest that thinner wear-course pavements made from appropriately designed taconite-based mixes can match or exceed the service life of conventional MnDOT Level 4 mixtures. If extended service life is realized, then taconite fine aggregate could be a cost-effective choice at end-user locations where high-quality local aggregate sources are lacking or absent. These enhanced performance attributes can add intrinsic value to taconite materials and make them more desirable to use and more cost-effective to transport longer distances, thereby improving and broadening their near- and long-term potential for regional and national highway infrastructure projects.Item Review of the Applications of Microwave Heating for Asphalt Pavement Maintenance(2021-06) Calhoon, ThomasThe propagation of microcracks into more serious pavement distresses is a major concern for asphalt pavements. Much work has been done to accelerate and control the asphalt self-healing of microcracks through the application of external heating methods including microwave heating. This thesis provides a state of the art of application of microwave heating of asphalt pavements, including self-healing. The principles of microwave heating, components of a microwave system, and different types of microwave systems are discussed. Then, an extensive literature review on the use of microwaves on asphalt pavements is presented. The review covers several applications of microwave heating on asphalt pavements and additives that enhance the microwave-absorbing capabilities of asphalt materials. Then, the results of a laboratory fatigue-heal cycle experiment are presented. The results demonstrate the ability of microwave heating to activate asphalt self-healing. Then, a 1D microwave heat transfer model is presented. A sensitivity analysis is performed on several model parameters. The analysis reveals that some parameters, such as thermal conductivity, do not significantly impact the microwave heating outcome, while some, such as applied microwave power density, do. Finally, recommendations are made for future work including field trials of discussed applications and implementation of the presented model in a computer application.Item Warm-Mix Asphalt(Transportation Engineering and Road Research Alliance (TERRA), 2009-06) Transportation Engineering and Road Research Alliance (TERRA)This 2-page fact sheet provides information about warm-mix asphalt and its implementation in Minnesota.