Filtering by
- All Subjects: Transportation
- Genre: Masters Thesis
- Creators: Cooke, Nancy J.
- Creators: Mamlouk, Michael S.
Crumb rubber use in asphalt mixtures by means of wet process technology has been in place for several years in the United States with good performance record; however, it has some shortcomings such as maintaining high mixing and compaction temperatures in the field production. Organosilane (OS), a nanotechnology chemical substantially improves the bonding between aggregate and asphalt by modifying the aggregate structure from hydrophilic to hydrophobic contributing to increased moisture resistance of conventional asphalt mixtures. Use of Organosilane also reduces the mixing and compaction temperatures and facilitates similar compaction effort at lower temperatures. The objective of this research study was first to perform a Superpave mix design for Crumb Rubber Modified Binder (CRMB) gap-graded mixture with and without Organosilane; and secondly, analyse the performance of CRMB mixtures with and without Organosilane by conducting various laboratory tests. Performance Grade (PG) 64-22 binder was used to create the gap-graded Hot Mix Asphalt (HMA) mixtures for this study. Laboratory tests included rotational viscometer binder test and mixtures tests: dynamic modulus, flow number, tensile strength ratio, and C* fracture test. Results from the tests indicated that the addition of Organosilane facilitated easier compaction efforts despite reduced mixing and compaction temperatures. Organosilane also modestly increased the moisture susceptibility and resistance to crack propagation yet retaining equal rutting resistance of the CRMB mixtures.
The literature and results of the present study suggest perceived trustworthiness for safety of the automation and the brand of the automation, could together impact trust. Results revelated that brands closely related to the trust-based attributes, Confidence, Secure, Integrity, and Trustworthiness were expected to produce autonomous vehicle technology that performs in a safer way. While, brands more related to the trust-based attributes Harmful, Deceptive, Underhanded, Suspicious, Beware, and Familiar were expected to produce autonomous vehicle technology that performs in a less safe way.
These findings contribute to both the fields of Human-Automation Interaction and Consumer Psychology. Typically, brands and automation are discussed separately however, this work suggests an important relationship may exist. A deeper understanding of brand trust as it relates to autonomous vehicles can help producers understand potential for over or under reliance and create safer systems that help users calibrate trust appropriately. Considering the impact on safety, more research should be conducted to explore brand trust and expectations for performance between various brands.
exponential rate, expected to alter the very foundations of our transportation system within the next 10-25 years. A crucial interaction has been born out this new technology: Human and automated drivers operating within the same environment. Despite the well- known dangers of automobiles and driving, autonomous vehicles and their consequences on driving environments are not well understood by the population who will soon be interacting with them every day. Will an improvement in the understanding of autonomous vehicles have an effect on how humans behave when driving around them? And furthermore, will this improvement in the understanding of autonomous vehicles lead to higher levels of trust in them? This study addressed these questions by conducting a survey to measure participant’s driving behavior and trust when in the presence of autonomous vehicles. Participants were given several pre-tests to measure existing knowledge and trust of autonomous vehicles, as well as to see their driving behavior when in close proximity to autonomous vehicles. Then participants were presented with an educational intervention, detailing how autonomous vehicles work, including their decision processes. After examining the intervention, participants were asked to repeat post-tests identical to the ones administered before the intervention. Though a significant difference in self-reported driving behavior was measure between the pre-test and post- test, there was no significant relation found between improvement in scores on the education intervention knowledge check and driving behavior. There was also no significant relation found between improvement in scores on the education intervention knowledge check and the change in trust scores. These findings can be used to inform autonomous vehicle and infrastructure design as well as future studies of the effects of autonomous vehicles on human drivers in experimental settings.
United States Air Force airfield PAVER pavement management system enterprise data was reviewed for 67 networks. The distress survey extents and severity fields were joined with treatment costs estimated using RSMeans to determine the costliest distress. In asphalt surfaced pavements Longitudinal/transverse cracking, weathering, and block cracking resulted in the most pavement condition index (PCI) deducts while the costliest distresses are weathering, block cracking and longitudinal cracking. In portland cement concrete surfaced pavements linear cracking, joint seal damage, and joint spalling resulted in the most PCI deducts while the costliest distresses are joint seal damage, linear cracking, and corner spalling. The results of this data were then compared to airfield attributes: Pavement Temperature Group, Dominant American Association of State Highway and Transportation Officials (AASHTO) Soil Classification, Pavement- Transportation Computer Assisted Structural Engineering (PCASE) Climate Zone, and years since last maintenance. Maps showing the Pavement Temperature Group, Dominant AASHTO Soil Classification, and PCASE Climate Zone are included in Appendix A. Alligator cracking is most prevalent at the airfields with PTG 64-34 (Ellsworth, Fairchild, Hill, and Offutt) and 58-22 (Niagara and Vandenberg). Rutting is most prevalent at PTG 64-34 (Ellsworth, Fairchild, Hill, and Offutt). An increasing trend of joint spalling, corner spalling, and corner break with decreasing soil quality (AASHOTO A-1 to A-8 soils). The PCASE Climate Zone Cost Indices the cost index for weathering is approximately double in the moist region over the dry region. The cost index for block cracking is approximately double in the cold region over the hot region. It is recommended that the agency review its pavement performance modeling in the pavement management system to increase the recommendation of pavement preservation treatments and review the use of higher quality materials for pavement maintenance treatments.