Dr. Amit Bhasin discusses infrastructure, materials, and pavements with USIT students at UT Austin, August 1, 2012
Dr. Amit Bhasin, Assistant Professor in the Department of Civil, Architectural and Environmental Engineering at The University of Texas at Austin, presented “Infrastructure Materials and Pavements – The Road Ahead” on August 1, 2012, at the Cockrell School of Engineering. The talk was part of a series of presentations by and for students engaged in transportation research.
This summer at the Cockrell School of Engineering, students exploring transportation research as a potential career are seeing the many directions that such a career can take them. UT Austin professors, Center for Transportation (CTR) researchers, and students are presenting topics of interest as part of the Undergraduate Summer Internship in Transportation (USIT). USIT is sponsored by the Advanced Institute for Transportation Infrastructure Engineering and Management, an organization whose mission is to increase the number, quality, and diversity of professionals entering the transportation sector.
“Materials are expensive and finite,” Dr. Bhasin said. “We have to be very wise in our use of them.” With two million miles of paved highways in the U.S. that must be maintained and expanded, materials for road construction are one of the most valuable capital assets in the country.
Picture is from http://www.hotmix.org
In the past, Bhasin explained, materials were extracted from the ground and used with little modification or precision. Today, the process of obtaining, testing, and adapting materials to specific uses has been refined, due in part to advances made in transportation research. Materials are carefully utilized in ways that increase benefits while keeping costs down.
Dr. Bhasin gave an example of one such refinement, where surfactants are added to asphalt binders to obtain the required viscosity at lower temperatures. Working the material at lower temperatures allows less energy to be used during materials processing. Less heat reduces fumes from the surface of the heated binder. An additional benefit of working at lower temperatures is that, by reducing oxidization during construction, the lifetime of the pavement is extended.
To address environment and sustainability concerns, new technologies have been developed to reduce emissions and energy consumption while increasing the use of recyclable materials such as recycled pavements and shingle waste. Bhasin noted that is it important to do extensive research on the effects of making changes to materials used in construction. If a change had unintended negative effects, it would be costly.
Transportation researchers thoroughly test new materials and methods before they are put to wide-scale use in road construction. Engineers and researchers use mechanistic modeling as one method to test proposed changes to materials.
Bhasin explained how the material properties of asphalt change, based on such variables as traffic loads, speeds, temperature, and the age of the pavement. One size does not fit all when preparing asphalt mixtures for pavement construction. For example, a different pavement materials mix would be used for a road such as Dean Keaton (bordering the UT Austin campus) compared to a pavement mix applied to downtown Austin’s I-35 highway. Similarly, a different mix composition would be chosen for a freeway in Austin compared to a highway in Dallas, in part due to the variant weather conditions.
Engineers must be trained to understand this complexity when designing and planning a roadway project and take the many variations that affect material properties of asphalt pavement into consideration.
Even rocket science can come into play with analyzing pavement cracking. “Advances in research, including rocket science, have been adapted to pavement and materials research,” Bhasin said.
Dr. Bhasin gave an example of solid rocket fuel used to propel spaceships into the atmosphere. Solid rocket fuel has an open surface in the middle and is stacked into long cones of fuel. A flame is dropped into the center of the cone of fuel cells, which lights the fuel as it descends. Scientists observed that solid fuel sometimes develops microcracks at the surface of the inner core, which extend into the solid fuel mass. This cracking could lead to uneven burn inside the solid fuel core, causing the rocket to explode. Research has been conducted in partnership with NSF to study microcracking that is applicable to pavements on earth as well as to rocket propulsion.
Working with NSF, researchers create knowledge that serves the entire scientific community. At the present time, Bhasin said, work is being done to study self-healing materials.
Much research is needed in the field of transportation research, Bhasin said, referring to the National Asphalt Roadmap, prepared by the FHWA, AASHTO, and other transportation authorities, which contains more than 200 problem statements about areas where research is needed.
Research done for TxDOT and NCHRP includes such studies as assessing the long-term impact of warm-mix asphalt technology and recommended best practices and implementing new specifications for asphalt binders.
Studies planned in partnership with FYWA and USDOT include testing for accurate and efficient test methods to identify better-performing binders and modeling of fatigue, fracture, and self-healing in pavement materials to predict performance of mixtures in the field.
Research designed to meet industry needs includes assistance with innovation of new materials and chemical modifiers to improve the performance of asphalt binders, facilitate increased use of recyclable materials in asphalt mixtures, and to facilitate the production and placement of mixtures under varying conditions.
Dr. Bhasin’s areas of research study include mechanistic modeling of fatigue cracking and durability of pavement materials, self healing properties of bituminous materials, surface properties and interfacial adhesion characteristics of materials, and test methods to characterize performance of infrastructure material. Dr. Basin can be reached at firstname.lastname@example.org.
For more information on Dr. Bhasin, visit his bio page at the Cockrell School of Engineering. http://www.caee.utexas.edu/faculty-directory/profiles/amit-bhasin.html
Faculty and professional researchers presenting topics of interest this summer include Dr. Zhanmin Zhang, Dr. C. Michael Walton, Rob Harrison, Dr. Kara Kockelman, Dr. Randy B. Machemehl, Dr. Chandra Bhat, Dr. Stephen Boyles, Lisa Loftus-Otway, and Dr. Amit Bhasin.
Students participating in the USIT internship are exposed to active transportation research programs that cover a wide range of topics, including systems analysis, materials, design, management, traffic engineering and planning, modeling, testing, and multimodal systems. USIT is sponsored by the Advanced Institute for Transportation Infrastructure Engineering and Management, an organization whose mission is to increase the number, quality, and diversity of professionals entering the transportation sector.
Many of the transportation research projects discussed at USIT events are conducted through the Center for Transportation Research. UT Austin faculty and student researchers perform the research and produced research reports and products. Much of the work is funded by the Texas Department of Transportation.
Links to More Information
Civil, Architectural & Environmental Engineering (CAEE) at UT Austin