Project

Development of a Novel Material with thermal resistance properties for asphalt mixtures.

Goal: One of the biggest challenges that asphalt pavement must overcome is its thermal susceptibility. Thermal susceptibility of the asphalt can increase problems related to permanent deformation at high temperatures, and the expansion-contraction phenomenon trigger the appearance of thermal cracking. Also, there is a common worldwide interest in environmental issues and pavements. How to save energy and mitigate the urban heat island (UHI) effect are topics that have been drawing the attention of researches and industrial organizations. Pavements play an important role in mitigating the urban heat island effect. Globally, about 90% of roadways are made of asphalt mixtures. The objective of my research involves the development and testing of an innovative product in the modification of asphalt mixtures to function as a material with unique thermal resistance properties for better durability and urban cooling. Earlier in the research, it was possible to overcome many barriers related to the inception of the project in transforming what started as a laboratory task to a successful field implementation of a product to potentially be used in one of the largest industries in the world. About 33 tons of unmodified and modified asphalt mixtures were manufactured at an asphalt plant to build pavement slabs and test road sections. Thermocouples installed at top and bottom during the construction process collected data every 30 minutes daily. This data was valuable in understanding the temperature fluctuation of the pavement. Laboratory expansion-contraction test was developed and used in the analysis. The modified mixtures showed lower temperature gradient, which means lower strains development in the pavement. These results are desirable in two aspects: reducing overall pavement temperatures and suppressing the temperature fluctuation between maximum and minimum daily temperatures, a key to reduce or minimize thermal cracking. Other research activities included the use of the AASHTOWare Pavement Design software, and life cycle cost assessment. Based on these preliminary analyses, the modified pavement would perform well. Moreover, the new product emerges as a competitive alternative for being used in future asphalt pavement production

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Project log

Carlos Obando
added 2 research items
Nowadays, there is a common worldwide interest in environmental issues and pavements. How to save energy and mitigate the urban heat island (UHI) effect are topics that are drawing the attention of different researches and industrial organizations. In road infrastructure, one of the important properties addressing environmental and UHI aspects of pavements is the determination of the thermal conductivity. Asphalt concrete represents the third most widely used resource in the world, with asphalt-paved roads being its principal usage. One of the most important components of asphalt concrete is bitumen. Bitumen is a viscoelastic material susceptible to temperature changes. The determination of the bitumen´s thermal conductivity becomes very important in understanding and improving its thermal performance. There are very few test methods and equipment to measure thermal conductivity of bitumen (asphalt binders). Some are expensive and require special equipment and instrumentation. This study developed and validated a simplified testing technique to measure thermal conductivity of asphalt binders. This test is a steady state-based method to estimate the thermal conductivity of asphalt binders using cylindrical samples poured into a silicon mold. The method was validated using material of known thermal conductivity. Eighteen samples of different binder grades were tested, and the test results were repeatable and within known thermal conductivity values. Sensitivity analysis and accuracy of the proposed method were validated modifying the asphalt binder with a material with a very low thermal conductivity. This method to estimate thermal conductivity of bitumen samples was found to provide an affordable alternative test procedure with good accuracy and precision. Keywords: Thermal conductivity, bitumen, steady-state method, heat transfer rate
Carlos Obando
added a project goal
One of the biggest challenges that asphalt pavement must overcome is its thermal susceptibility. Thermal susceptibility of the asphalt can increase problems related to permanent deformation at high temperatures, and the expansion-contraction phenomenon trigger the appearance of thermal cracking. Also, there is a common worldwide interest in environmental issues and pavements. How to save energy and mitigate the urban heat island (UHI) effect are topics that have been drawing the attention of researches and industrial organizations. Pavements play an important role in mitigating the urban heat island effect. Globally, about 90% of roadways are made of asphalt mixtures. The objective of my research involves the development and testing of an innovative product in the modification of asphalt mixtures to function as a material with unique thermal resistance properties for better durability and urban cooling. Earlier in the research, it was possible to overcome many barriers related to the inception of the project in transforming what started as a laboratory task to a successful field implementation of a product to potentially be used in one of the largest industries in the world. About 33 tons of unmodified and modified asphalt mixtures were manufactured at an asphalt plant to build pavement slabs and test road sections. Thermocouples installed at top and bottom during the construction process collected data every 30 minutes daily. This data was valuable in understanding the temperature fluctuation of the pavement. Laboratory expansion-contraction test was developed and used in the analysis. The modified mixtures showed lower temperature gradient, which means lower strains development in the pavement. These results are desirable in two aspects: reducing overall pavement temperatures and suppressing the temperature fluctuation between maximum and minimum daily temperatures, a key to reduce or minimize thermal cracking. Other research activities included the use of the AASHTOWare Pavement Design software, and life cycle cost assessment. Based on these preliminary analyses, the modified pavement would perform well. Moreover, the new product emerges as a competitive alternative for being used in future asphalt pavement production