Rutting and Fatigue Performance Evaluation of Asphalt Emulsion Modified using Asphaltenes

• Author / Creator

  Basavarajappa, Manjunath Sultanipura

• Road network plays a vital role in a country’s infrastructure by providing easy access from one coast to the other coast of the country through transportation which helps in supply of goods and movement of people. Basically, roads are designed and constructed to withstand specific traffic loading and climate conditions. However, the increase in traffic volume and allowable axle load weights leads to the increases in stresses exerted on pavement which subsequently results in rapid deterioration of pavement structures before reaching their intended design life. To overcome this issue, the preservation and treatment of pavement structure have become an important technique for the pavement industry. Modification of asphalt mixture is another method used to improve the performance of pavement in order to avoid the early stage of failure. The use of asphalt emulsion in pavement construction is one such a method to provide a well maintained and efficient road network. Asphalt emulsion is recently raising its popularity in pavement construction, and preservation treatment works like slurry seals, chip seals, micro-surfacing, fog seals and tack coats because of its low-temperature applications, lower viscosity and lower energy consumption. Asphalt emulsions are normally used for cold mix applications and have several advantaged over hot mix applications such as eco-friendly, easy to handle, and does not required to be heated at high temperature for its application instead it can be used at ambient temperature which provides safer working conditions by eliminating dangerous toxic fumes.
  For better understanding of asphalt emulsion properties, this research focused on investigating the application of asphalt emulsion modified using asphaltenes for base course layer application. The asphaltenes used in this research were derived from Alberta oil sands. Two types of asphaltenes from different sources were used in this study. For modification, a typical hand mixing procedure was used to mix asphaltenes with asphalt emulsion. Mix design was prepared in accordance with the standard method to determine the asphalt emulsion and water content to use in the preparation of asphalt mixture. To compare the results, various proportions of asphaltenes content were used for asphalt emulsion modification. Different types of tests were performed on a modified mixture to analyze the rutting and fatigue properties. The Marshall stability, indirect tensile strength (ITS), and Hamburg wheel tracking tests were performed on modified and unmodified asphalt mixture in accordance with ASTM/AASHTO standards. Also, indirect tensile asphalt cracking test (IDEAL-CT) was conducted to understand the cracking resistance of modified mixtures. To characterize the rheological properties of asphaltenes modified asphalt emulsion, asphalt emulsion residues were recovered using low-temperature evaporation technique. The high-temperature properties and dynamic mechanical analysis were performed on recovered residues using a dynamic shear rheometer (DSR).
  Results from the study indicate that adding asphaltenes for asphalt emulsion modification improved the performance of both the asphalt mixture and the residue significantly. The Marshall stability of the asphaltenes modified samples is found to increase by 50-100% compared to the unmodified samples. It was also observed that tensile strength and rutting resistance of the modified mixtures were improved considerably than the unmodified mixture. The outcome of the Hamburg wheel tracking test results indicates that the rutting resistance index (RRI) of the modified mixtures was found to increase twice that of the unmodified mixture. From IDEAL-CT analysis, it was noticed that the fracture energy of the modified samples were increased, but the cracking tolerance index (CTIndex) was reduced for the modified mixture. However, the rheology tests specified that the high limiting temperature of the modified samples were increased by 30 °C to 40 °C compared to the unmodified sample. Whereas from the dynamic mechanical analysis, it was found that asphaltenes modification improves the elastic property of the asphalt emulsion, but at low-frequency range, more stiffness behaviour was observed.

• Subjects / Keywords

  • Pavement Engineering

• Graduation date

  Spring 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-0kxz-cz02

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.