@article{narayan_khosla_2022, title={Self-organization of amorphous Q-carbon and Q-BN nanoballs}, volume={192}, ISSN={["1873-3891"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85125815590&partnerID=MN8TOARS}, DOI={10.1016/j.carbon.2022.03.003}, abstractNote={This paper reports for the first time the formation and self-organization of amorphous Q-carbon and Q-BN nanoballs. This is accomplished by nanosecond laser melting of carbon and BN layers, respectively, in a highly undercooled state and subsequent rapid cooling at normal pressures in air. The size of these Q-carbon and Q-BN nanoballs having a uniform size can be varied from 5 to 100 nm, and self-organized along rings and strings by manipulating laser, carbon film, and substrate parameters. It is envisaged that self-organization is promoted by the undercooling and it occurs along strings and rings, which are formed by the tetrahedral alignment in <100> and <110> directions, respectively. These nanoballs were characterized by HRSEM/TEM/STEM/EELS and Raman to confirm the phase purity and bonding characteristics. The Q-carbon balls exhibit robust ferromagnetism and field emission in pure and undoped form and show highest BCS superconducting transition temperature upon doping with boron. The ferromagnetism in Q-carbon balls can be varied with size and achieve higher coercively than thin films, and these balls can be coated with drugs for targeted delivery. In view of these properties, nanoballs are expected to find novel applications ranging from targeted delivery to nanosensing and superconducting qubits.}, journal={CARBON}, author={Narayan, J. and Khosla, N.}, year={2022}, month={Jun}, pages={301–307} }
 @article{kusam_malladi_tayebali_khosla_2017, title={Laboratory Evaluation of Workability and Moisture Susceptibility of Warm-Mix Asphalt Mixtures Containing Recycled Asphalt Pavements}, volume={29}, ISSN={["1943-5533"]}, DOI={10.1061/(asce)mt.1943-5533.0001825}, abstractNote={AbstractWarm mix asphalt (WMA) and recycled asphalt pavements (RAP) are two popularly used sustainable technologies in pavement industry. Because RAP materials contain aged binder, its use is limit...}, number={5}, journal={JOURNAL OF MATERIALS IN CIVIL ENGINEERING}, author={Kusam, Abhilash and Malladi, Haritha and Tayebali, Akhtarhusein A. and Khosla, N. Paul}, year={2017}, month={May} }
 @article{malladi_ayyala_tayebali_khosla_2015, title={Laboratory Evaluation of Warm-Mix Asphalt Mixtures for Moisture and Rutting Susceptibility}, volume={27}, ISSN={["1943-5533"]}, DOI={10.1061/(asce)mt.1943-5533.0001121}, abstractNote={AbstractSince its introduction, warm mix asphalt (WMA) has garnered a lot of attention and interest from the pavement industry as a promising technology to replace the conventional hot mix asphalt (HMA). Despite its many benefits, including reducing emissions and fuel usage, definitive answers on the feasibility of replacing HMA pavements with WMA are yet to be answered. A major concern for WMA is susceptibility to moisture-induced damage. In this research study, mixtures prepared using three WMA technologies- viz. Sasobit, Advera WMA and the Foamer were evaluated for their moisture susceptibility and permanent deformation in comparison with an HMA mixture. Tensile strength ratio (TSR) and asphalt pavement analyzer (APA) tests were conducted on these mixtures. Results show that moisture-based WMA technologies (Advera and Foamer) are more susceptible to moisture damage. However, rut depths evaluated using APA, even for moisture-conditioned specimens, indicated WMA performance on par with that of HMA. Even ...}, number={5}, journal={JOURNAL OF MATERIALS IN CIVIL ENGINEERING}, author={Malladi, Haritha and Ayyala, Dinesh and Tayebali, Akhtarhusein A. and Khosla, N. Paul}, year={2015}, month={May} }
 @inproceedings{ayyala_malladi_khosla_tayebali_2014, title={Evaluation of warm mix asphalt technology for surface mixtures}, DOI={10.1201/b17219-88}, abstractNote={Economic, environmental, and engineering benefits led to the rapid implementation of Warm-Mix Asphalt (WMA) during the past decade. While WMA technologies are generally performing well to date, development of standard mix design protocols continues and performance questions remain. This study evaluated laboratory conditioning protocols for WMA to simulate early life when they are more moisture susceptible and proposed 2 hours at 116°C for mix design and reheating to this temperature for quality assurance for all WMA technologies except foaming which requires reheating to 135°C. Next, WMA was shown to be more moisture susceptible as compared to Hot-Mix Asphalt in the early life based on a comprehensive analysis of three standard laboratory tests (wet and dry indirect tensile strengths and resilient modulus and their ratios and Hamburg Wheel Tracking Test stripping parameters) from four field projects that included nine WMA mixtures. Finally, an evaluation of performance evolution showed that WMA can overcome this vulnerability to moisture after a summer of aging and proposed 5 days oven aging at 85°C to capture this effect in the laboratory. Proposed conditioning protocols, aging protocols, and criteria for the tests utilized are provided for WMA mix design and analysis to preclude moisture susceptibility.}, booktitle={Asphalt Pavements, vol 1}, author={Ayyala, D. and Malladi, H. and Khosla, N. P. and Tayebali, A. A.}, year={2014}, pages={701–708} }
 @article{khosla_ayyala_2013, title={A Performance-Based Evaluation of Superpave Design Gyrations for High Traffic Surface Mixes}, volume={104}, ISSN={["1877-0428"]}, DOI={10.1016/j.sbspro.2013.11.103}, abstractNote={The number of design gyrations (Ndes) is an extremely important parameter in the asphalt concrete mix design procedure using the Superpave method. The choice of Ndes is a function of total traffic during the pavement service life, expressed in ESALs. Asphalt concrete mixes for higher traffic levels are compacted to a higher Ndes as a denser mix resists rutting more effectively. However, this leads to a lower design asphalt content, which decreases fatigue performance of the mix. Therefore, a performance-oriented approach to determine Ndes was developed that optimizes mix performance with respect to both rutting and fatigue cracking. In this paper, the research methodology adopted to compare the relative performance of surface mixes with 12.5 mm nominal maximum aggregate size is presented, along with recommended Ndes values for C and D-level mixes, designed to handle traffic levels of 3-30 Million and greater than 30 Million ESALs, respectively. Asphalt concrete mixes were designed at Ndes levels of 50, 75, 100 and 125 gyrations to determine asphalt content using Superpave design method. Dynamic modulus (E*) was measured at design asphalt content for different gyration levels using the Asphalt Mixture Performance Tester device. The E* data and corresponding binder properties were used as input in the AASHTO Darwin-ME software to predict rutting and fatigue performance of the mixes by assuming a model pavement section and appropriate traffic levels. Relative performance indicators were developed for both rutting and fatigue, and plotted against the asphalt content to determine optimum Ndes. For both surface mixes, the optimum Ndes value was determined to be 85 gyrations.}, journal={2ND CONFERENCE OF TRANSPORTATION RESEARCH GROUP OF INDIA (2ND CTRG)}, author={Khosla, N. Paul and Ayyala, Dinesh}, year={2013}, pages={109–118} }
 @article{visintine_khosla_tayebali_2013, title={Effects of higher percentage of recycled asphalt pavement on pavement performance}, volume={14}, ISSN={["1468-0629"]}, DOI={10.1080/14680629.2013.779310}, abstractNote={The recycling of asphalt pavements has become a very routine procedure throughout the country. Research has shown that the recycled asphalt pavement (RAP) recovered from construction sites still contains usable materials, both in the recycled aggregates and recycled binder. The fatigue life and rut resistance of mixtures containing various amounts of recycled asphalt pavement (RAP) were compared with a virgin mixture. The fatigue life and rut resistance of the mixtures were calculated from laboratory testing using Frequency Sweep Testing using Superpave Simple Shear Tester (SST) and Repeated Simple Shear Tests using (SST) device. The SHRP A-003A surrogate models and the Asphalt Institute models were both be used in order to predict pavement performance using the results from the Frequency Sweep Testing and the Repeated Simple Shear Test.}, number={2}, journal={ROAD MATERIALS AND PAVEMENT DESIGN}, author={Visintine, Beth and Khosla, N. Paul and Tayebali, Akhtar}, year={2013}, month={Jun}, pages={432–437} }
 @inbook{khosla_birdsall_kawaguchi_2000, title={Evaluation of moisture susceptibility of asphalt mixtures: Conventional and new methods}, ISBN={0309067316}, DOI={10.3141/1728-07}, abstractNote={ Evaluation of a mixture’s moisture sensitivity is currently the final step in the Superpave® volumetric process. This step is accomplished by using AASHTO T-283, which tolerates a range of values in the test variables of sample air voids and degree of saturation. The tensile strength ratios determined for the mixes in this study varied with the air void level and degree of saturation. Although the levels of conditioning were within the specifications for AASHTO T-283, test results both passed and failed the 80 percent criterion, depending on the severity of conditioning. An alternative to measuring indirect tensile strength is a test that evaluates a mixture’s fundamental material properties. A relatively simple test is proposed that measures the cohesion and friction angle for asphalt mixtures. In addition, the Superpave shear tester (SST) was incorporated as a tool in evaluating moisture sensitivity. The proposed axial test determined the cohesion and angle of friction of the mix. The friction angle remained constant for the conditioned and unconditioned samples. Hence, conditioning of the samples had practically no effect on the mixture’s internal friction. The cohesion of the mix decreased when the mix was subjected to conditioning. The reduction in cohesion was greater in the case of the Fountain aggregate, which is known to be highly moisture susceptible. The shear tests to failure performed on the SST confirmed the results of the new apparatus, which provides a simple method for determining a mixture’s cohesion. The loss of cohesion due to conditioning can be used to determine a mixture’s moisture susceptibility. The three antistrip additives used in this study were hydrated lime, a liquid amine, and a liquid phosphate ester. }, number={1728}, booktitle={Asphalt binders, 2000}, publisher={Washington, DC: National Academy Press}, author={Khosla, N. P. and Birdsall, B. G. and Kawaguchi, S.}, year={2000}, pages={43–51} }
 @inbook{tayebali_khosla_waller_1999, title={Evaluation of superpave repeated shear at constant height test to predict rutting potential of mixes: Performance of three pavement sections in North Carolina}, ISBN={0309071070}, DOI={10.3141/1681-12}, abstractNote={ The repeated shear at constant height (RSCH) test to predict the rutting potential of asphalt aggregate mixes based on field performance of pavement sections in North Carolina has been evaluated. Three pavement sections in Buncombe, McDowell, and Montgomery counties were selected based on the degree of rutting severity experienced after several years in service. The pavement section in Buncombe County showed no rutting, whereas those in McDowell and Montgomery counties showed light and severe rutting distress, respectively. Results of this study indicated that the RSCH test can clearly identify the well-performing versus poorly performing mixes (i.e., Buncombe versus Montgomery counties). Although previous studies in which the French pavement rutting tester and the Georgia loaded-wheel tester were used indicated early rutting of the pavement in Buncombe County, the RSCH test indicated that the mix was not susceptible to excessive rutting—in line with field experience of no significant pavement distress observed in this pavement. For Montgomery County, the RSCH test clearly showed that the mix was susceptible to excessive rutting with the wheelpath cores distinctly showing potential for tertiary flow—in agreement with experience of significant rutting distress observed in this pavement. }, number={1681}, booktitle={Hot-mix asphalt mixtures}, publisher={Washington, DC: National Academy Press}, author={Tayebali, A. A. and Khosla, N. P. and Waller, H. F.}, year={1999}, pages={97} }
 @inproceedings{bienvenu_khosla_tayebali_1998, title={Development of a binder blending chart for cold-recycled mix design using the dynamic shear rheometer}, volume={1652}, booktitle={Seventh International Conference on Low-Volume Roads 1999  (Transportation research record; 1652)}, publisher={Washington, D.C.: National Academy Press}, author={Bienvenu, M. E. and Khosla, N. P. and Tayebali, A. A.}, year={1998} }
 @inbook{tayebali_malpass_khosla_1998, title={Effect of mineral filler type and amount on design and performance of asphalt concrete mixtures}, ISBN={0309064546}, number={1609}, booktitle={Superpave: Binder specifications, mixture design and construction}, publisher={Washington, DC: Transportation Research Board}, author={Tayebali, A. A. and Malpass, G. A. and Khosla, N. P.}, year={1998}, pages={36–43} }
 @book{tayebali_malpass_khosla_waller_1998, title={Evaluation of applicability of SUPERPAVE test methods to predict performance and tertiary flow potential of asphalt-aggregate mixes containing unmodified and modified asphalt binders}, publisher={Raleigh, NC: Center for Transportation Engineering Studies, North Carolina State University}, author={Tayebali, A. A. and Malpass, G. and Khosla, N. P. and Waller, H. F.}, year={1998} }
 @inproceedings{khosla_satish_kim_kim_1997, title={A comparative study of performance of different designs for flexible pavements}, booktitle={Eighth International Conference on Asphalt Pavements, August 10-14, 1997, Seattle, Washington: Proceedings.}, publisher={Seattle, Wash.: University of Washington}, author={Khosla, N. P. and Satish, S. and Kim, N. and Kim, Y. R.}, year={1997}, pages={328–335} }