ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- Creators: Kaloush, Kamil
Description
Thermal susceptibility is one of the biggest challenges that asphalt pavements must overcome. Asphalt mixture’s thermal susceptibility can increase problems related to permanent deformation, and the expansion-contraction phenomenon triggers thermal cracking. Furthermore, there is a common worldwide interest in environmental impacts and pavements. Saving energy and mitigating the urban heat island (UHI) effect have been drawing the attention of researchers, governments, and industrial organizations. Pavements have been shown to play an important role in the UHI effect. Globally, about 90% of roadways are made of asphalt mixtures. The main objective of this research study involves the development and testing of an innovative aerogel-based product in the modification of asphalt mixtures to function as a material with unique thermal resistance properties, and potentially providing an urban cooling mechanism for the UHI. Other accomplishments included the development of test procedures to estimate the thermal conductivity of asphalt binders, the expansion-contraction of asphalt mixtures, and a computational tool to better understand the pavement’s thermal profile and stresses. Barriers related to the manufacturing and field implementation of the aerogel-based product were overcome. Unmodified and modified asphalt mixtures were manufactured at an asphalt plant to build pavement slabs. Thermocouples installed at top and bottom collected data daily. This data was valuable in understanding the temperature fluctuation of the pavement. Also, the mechanical properties of asphalt binders and mixtures with and without the novel product were evaluated in the laboratory. Fourier transform infrared (FTIR) and scanning electron microscope (SEM) analyses were also used to understand the interaction of the developed product with bituminous materials.
The modified pavements showed desirable results in reducing overall pavement temperatures and suppressing the temperature gradient, a key to minimize thermal cracking. The comprehensive laboratory tests showed favorable outcomes for pavement performance. The use of a pavement design software, and life cycle/cost assessment studies supported the use of this newly developed technology. Modified pavements would perform better than control in distresses related to permanent deformation and thermal cracking; they reduce tire/pavement noise, require less raw material usage during their life cycle, and have lower life cycle cost compared to conventional pavements.
ContributorsObando Gamboa, Carlos Javier (Author) / Kaloush, Kamil (Thesis advisor) / Mamlouk, Michael (Committee member) / Ozer, Hasan (Committee member) / Fini, Elham (Committee member) / Zapata, Claudia (Committee member) / Arizona State University (Publisher)
Created2022
Description
The use of Reclaimed Asphalt Pavements (RAP) in newly produced asphalt mixtures has been gaining a wide attention from state Departments of Transportations (DOTs) during the past four decades. However, the performance of these mixtures in harsh and hot climate areas such as Phoenix, Arizona has not been carefully addressed. This research focuses on evaluating the laboratory and field performance of Hot Mix Asphalt Mixtures (HMA) produced with two different RAP contents 15%, and 25%. A road section was identified by the City of Phoenix where three test sections were constructed; the first being a control (0% RAP), the second and the third sections with 15% and 25% RAP contents, respectively. The 25% RAP mixture used a lower Performance Grade (PG) asphalt per local practices. During construction, loose HMA mixtures were sampled and transported to the laboratory for advanced material characterization.
The testing included Dynamic Modulus (DM) test to characterize the stiffness of the material, Flow Number (FN) test to characterize the rutting resistance of the mixtures, IDEAL CT test to characterize the crack initiation properties, C* Fracture test to investigate the crack propagation properties, Uniaxial Fatigue to evaluate fatigue cracking potential, and Tensile Strength Ratio test (TSR) to evaluate the moisture susceptibility. Field cores were obtained from each test section and were tested for indirect tensile strength characteristics. In addition, asphalt binder testing was done on the extracted and recovered binders.
The laboratory results, compared to the control mixture, indicated that adding 15% and 25% RAP to the mix did not have significant effect on the stiffness, improved the rutting potential, had comparable cracking potential, and gave an acceptable passing performance against potential moisture damage. The binder testing that was done on the extracted and recovered binders indicated that the blended RAP binder yields a high stiffness. Based on results obtained from this study, it is recommended that the City of Phoenix should consider incorporating RAP in their asphalt mixtures using these low to moderate RAP contents. In the future implementation process, it is also recommended to include specifications where proper mixture designs are followed and supported with some of the laboratory tests outlined in this research.
The testing included Dynamic Modulus (DM) test to characterize the stiffness of the material, Flow Number (FN) test to characterize the rutting resistance of the mixtures, IDEAL CT test to characterize the crack initiation properties, C* Fracture test to investigate the crack propagation properties, Uniaxial Fatigue to evaluate fatigue cracking potential, and Tensile Strength Ratio test (TSR) to evaluate the moisture susceptibility. Field cores were obtained from each test section and were tested for indirect tensile strength characteristics. In addition, asphalt binder testing was done on the extracted and recovered binders.
The laboratory results, compared to the control mixture, indicated that adding 15% and 25% RAP to the mix did not have significant effect on the stiffness, improved the rutting potential, had comparable cracking potential, and gave an acceptable passing performance against potential moisture damage. The binder testing that was done on the extracted and recovered binders indicated that the blended RAP binder yields a high stiffness. Based on results obtained from this study, it is recommended that the City of Phoenix should consider incorporating RAP in their asphalt mixtures using these low to moderate RAP contents. In the future implementation process, it is also recommended to include specifications where proper mixture designs are followed and supported with some of the laboratory tests outlined in this research.
ContributorsZalghout, Ali Ahmad (Author) / Kaloush, Kamil (Thesis advisor) / Fini, Elham (Committee member) / Mamlouk, Michael (Committee member) / Arizona State University (Publisher)
Created2019