The study of innovative pavements is of significant importance in geotechnical engineering in Brazil, due to the continued need to increase the network of roadways. This requires optimized projects, not only for economic, but also for technical reasons. Technical solutions that use geosynthetics in asphalt overlays have been identified to minimize fatigue and reflective cracks. However, the majority of the application of this technology has ignored the possible additional structural benefits brought by the inclusion of geosynthetics as reinforcement in asphalt layers. The objective of this research is to assess the reinforcement benefits of geogrids placed within asphalt overlays on the structural performance of flexible pavements. In addition, this study investigates the tensile-strain response of geogrids under traffic conditions, induced by cyclic wheel loads generated by a new accelerated pavement testing facility (APT) that was specifically developed for this research. The APT facility consists of a large steel testing box, in which field-scale pavement layers could be constructed. Pavement materials included subgrade soil, aggregate base, hot mix asphalt concrete, asphalt emulsion and a PVA geogrid. Pavement performance was assessed by applying a cyclic wheel load pressure of 700 kPa to the pavement surface. The pavement sections investigated in this study included a geogrid-reinforced and an unreinforced asphalt overlay sections, a single new geogrid-reinforced asphalt layer, and a geogrid-reinforced asphalt overlay with reduced base course thickness. A variety of sensors were used to measure asphalt concrete strains, surface plastic and elastic displacements, and induced traffic loads. Displacements along the geogrid specimens were measured using a tell-tail system. As result, several reinforcement mechanisms of this technique could be quantified in the present study. Polymeric geogrid reinforcements were found to have considerably reduced strains developed at the bottom of asphalt layers, as well as to have reduced vertical stresses in pavement lower layers. Resistance to rutting and lateral movement induced by the geogrids were also clearly evidenced in the presented study. The measurement of displacements along the geogrid provided understanding of the distribution of strains during traffic loading. A mobilized length was identified in geogrid-reinforced sections, showing that the bonding between geogrids and asphalt layers and the stiffness of the geogrid ensured satisfactory performance of the pavement sections. The results also illustrated that the lateral restraining mechanisms effect is a governing mechanism to improve the performance of the asphalt layers by the development of shearing resistance with the geogrids. Overall, it was concluded that geogrids within asphalt overlays act as reinforcement and not merely to delay cracks, providing enhanced performance to flexible pavement structures. / O estudo de pavimentos é de grande importância na Engenharia Geotécnica brasileira devido à crescente necessidade de melhora da situação da rede rodoviária nacional. Para tanto, o desenvolvimento e a aplicação de novas técnicas são necessários, principalmente no âmbito econômico. A técnica do uso de reforços geossintéticos em capa asfáltica é identificada como uma alternativa ao aumento da vida útil do pavimento através da mitigação de trincas por fadiga e de reflexão. No entanto, a maioria das aplicações desta técnica não correlaciona os benefícios estruturais da inclusão do geossintético na capa asfáltica para a melhora do desempenho global do pavimento. O objetivo desta pesquisa é investigar os benefícios estruturais no desempenho de pavimentos flexíveis trazidos pelo reforço de geogrelhas em camadas asfálticas. Ainda neste estudo, será investigada a reposta tensão-deformação destas geogrelhas sobre as condições de tráfego através do uso de ensaios acelerados de pavimento. Um equipamento foi desenvolvido para esta pesquisa e consiste numa caixa metálica de grande porte, em que seções de pavimento em escala real podem ser construídas. O desempenho das seções de pavimento foi avaliado com a aplicação de cargas cíclicas de roda com pressão de contato de 700 kPa. Os materiais que compõem as seções de pavimento incluem solo de subleito, brita graduada simples, concreto betuminoso usinado à quente, emulsão asfáltica e geogrelha de PVA. Foram estudadas uma seção com geogrelha como reforço no recapeamento da camada asfáltica, uma seção idêntica não reforçada, uma seção com uma única capa asfáltica reforçada com geogrelha e uma seção com geogrelha no recapeamento da camada asfáltica, porém com espessura de base reduzida em relação aos demais ensaios. Sensores nas camadas do pavimento mediram tensões e deformações, e deslocamentos plásticos e elásticos na superfície. Deslocamentos ao longo da geogrelha foram monitorados utilizando o sistema tell-tales. Como resultado, mecanismos de reforço foram identificados neste estudo. O uso de uma geogrelha polimérica reduziu consideravelmente as deformações na fibra inferior da capa asfáltica, assim como as tensões verticais nas camadas subjacentes do pavimento. Resistência à formação de trilhas de roda e solevamentos laterais foram também evidenciadas. As medidas de deslocamentos ao longo da geogrelha forneceram entendimento da distribuição de deformações durante o carregamento. Foi identificado o comprimento de geogrelha mobilizado durante os ensaios, mostrando que a aderência entre a geogrelha e as camadas asfálticas e a rigidez da geogrelha asseguraram o desempenho satisfatório das seções de pavimento. Os resultados também mostraram que o efeito do mecanismo de restrição lateral é um mecanismo que governa a melhora no desempenho da capa asfáltica com o uso da geogrelha através do desenvolvimento de resitência ao cisalhamento. Estas observações permitem concluir que a geogrelha na camada asfáltica atua como reforço e não apenas reduzindo a o potencial de trincamento, levando à um aumento no desempenho de estruturas de pavimentos flexíveis.

Cold Central Plant Recycling (CCPR) has been used by many state highway agencies to save material, money, time, and energy in pavement construction and rehabilitation. The objectives of this thesis were to: (1) perform an instrumented verification analysis, (2) evaluate the response and performance of two pavement configurations with a CCPR base layer through accelerated pavement testing (APT), and (3) construct models using mechanistic-empirical pavement design software for comparison with the APT results. The pavement configurations featured a 5-inch CCPR mixture with either a 3-inch or 1.5-inch SM-9.5D surface mixture. Each section was instrumented with strain gauges, pressure cells, and thermocouples. A heavy vehicle simulator (HVS) was used to load three replicate test sections in each lane, with the temperature controlled at 39°C at a depth of 1.5 inches. Results from the instrument verification analysis showed that the strain gauges and pressure cells used in the experiment recorded pavement responses with a high degree of repeatability. In addition, the loading condition variables (speed, wheel load, and tire inflation pressure) affected the response following the expected trends and did not affect the repeatability of the instruments. The average CV of all strain gauge and pressure cell signals was approximately 0.009 or 0.9%, and 0.004 or 0.4%, respectively. In terms of the rutting comparison, the sections with the 3-inch surface layer outperformed the sections with the thinner 1.5-inch surface layer. However, the age of the pavement at the start of testing significantly affected the rutting performance. After adjusting for the pavement age at the time of testing, the section with the thicker surface showed approximately half of the rutting of the section with the thinner surface. The results from preliminary ME Design analysis indicate that the software cannot model the studied APT sections using the default material properties and calibration factors available at the time of analysis. In particular, the software does not seem to be prepared to model the CCPR materials. / Master of Science / Accelerated Pavement Testing (APT) is a useful method for evaluating pavements, validating instrument responses, and developing pavement models. The APT uses a Heavy Vehicle Simulator (HVS) as a loading mechanism to simulate the effects of truck traffic on pavement sections. Strain gauges and pressure cells are installed in the pavement sections to monitor the pavement performance and record key points of strain and pressure. This thesis contains the findings and results of APT testing on two sections of pavement containing a cold central plant recycled (CCPR) base mixture; one section has a 3 inch surface mixture while the other has a 1.5 inch surface mixture. Also, an instrument verification exercise is conducted, and an ME Design model is constructed for comparison with the rutting results of the APT testing. Results from the instrument verification analysis showed that the strain gauges and pressure cells used in the experiment recorded pavement responses with a high degree of repeatability. In addition, the loading condition variables (speed, wheel load, and tire inflation pressure) affected the response following the expected trends and did not affect the repeatability of the instruments. In terms of the rutting comparison, the sections with the 3-inch surface layer outperformed the sections with the thinner 1.5-inch surface layer. However, the age of the pavement at the start of testing significantly affected the rutting performance. After adjusting for the pavement age at the time of testing, the section with the thicker surface showed approximately half of the rutting of the section with the thinner surface. The results from ME Design model indicate that the software cannot model the studied APT sections using the default material properties and calibration factors available at the time of analysis. In particular, the software does not seem to be prepared to model the CCPR materials.

At an average age of 42 years, 10% of the nation’s over 607,000 bridges are posted for load restrictions, with an additional 15% considered structurally deficient or functionally obsolete. While there are major concerns with decks in 75% of structurally deficient bridges, often weight and geometry of the deck further limit the load rating and functionality of the bridge. Traditional deck systems and construction methods usually lead to prolonged periods of traffic delays, limiting options for transportation agencies to replace or widen a bridge, especially in urban areas. The purpose of this study was to develop a new generation of ultra-lightweight super shallow solid deck systems to replace open grid steel decks on movable bridges and as well serve as a viable alternative in bridge deck replacements across the country. The study has led to a lightweight low-profile asymmetric waffle deck made with advanced materials. The asymmetry comes from the arrangement of primary and secondary ribs, respectively perpendicular and parallel to the direction of traffic. The waffle deck is made with ultrahigh performance concrete (UHPC) reinforced with either high-strength steel (HSS) or carbon fiber reinforced polymer (CFRP) reinforcement. With this combination, the deck weight was limited to below 21 psf and its overall depth to only 4 inch, while still meeting the strength and ductility demands for 4 ft. typical stringer spacing. It was further envisioned that the ultra-high strength of UHPC is best matched with the high strength of HSS or CFRP reinforcement for an efficient system and the ductile behavior of UHPC can help mask the linear elastic response of CFRP reinforcement and result in an overall ductile system. The issues of consideration from the design and constructability perspectives have included strength and stiffness, bond and development length for the reinforcement, punching shear and panel action. A series of experiments were conducted to help address these issues. Additionally full-size panels were made for testing under heavy vehicle simulator (HVS) at the accelerated pavement testing (APT) facility in Gainesville. Detailed finite element analyses were also carried out to help guide the design of this new generation of bridge decks. The research has confirmed the superior performance of the new deck system and its feasibility.

<p dir="ltr">This thesis investigates the embedment of Dynamic Wireless Power Transfer (DWPT) components within two pavement test sections, aiming to evaluate their mechanical and thermal responses. The integration of DWPT components into the pavement structure, while enabling dynamic power delivery to EVs, alters the conventional geometric design of a typical pavement, potentially influencing their short-term and long-term durability and integrity. Hence, to ensure the integrity and efficiency of both the embedded system and the surrounding structure, it is essential to understand how integrating these components influence the pavement's performance.</p><p dir="ltr">Conducted at the Accelerated Pavement Testing (APT) facility of the Indiana Department of Transportation (INDOT), the study evaluates over the course of 25,000 APT traffic passes, the mechanical and thermal responses of both, a flexible and rigid pavement test section. Each test section features a Charging Unit (CU), a concrete slab upon which the DWPT components are placed. The construction of the flexible pavement involved milling down 2 in. of the existing pavement surface, while the rigid pavement required complete demolition of the existing pavement. The flexible pavement’s CU is composed of Class A concrete and the rigid pavement's CU features magnetizable concrete, a type of concrete composed of ferrite particles embedded in a cement matrix. Among the two pavement sections, only the rigid pavement exhibited visible distress, identified as a mid-panel crack. Several factors contributed to the crack formation, including inadequate adhesion between concrete interfaces, concrete mix segregation, material variations, construction issues, and nonuniform load distribution. The manual construction procedures, which were employed to prevent disrupting the embedded DWPT components and sensor instrumentation, and the one-week gap between casting the CU and the surrounding slab might have further influenced the adhesion strength of the rigid pavement section.</p><p dir="ltr">By examining the construction techniques employed, challenges encountered, and resulting behavior of both pavement test sections, this study provides insights into the construction and performance implications of DWPT component integration into pavements, as evidenced by the responses observed in the test sections. This thesis thereby contributes to the ongoing research efforts on investigating the impact such integration has on the surrounding structure's integrity.</p>