Pavement and alignment design of a new rural road in the province of Bologna

This thesis aims to give a general view of pavement types all over the world, by showing the different characteristics of each one and its different life steps starting from construction, passing by maintenance and arriving until recycling phase. The flexible pavement took the main part of this work because it has been used in the last part of this thesis to design a project of a rural road. This project is located in the province of Bologna-Italy (‘Comune di Argelato’, 26 km in the north of Bologna), and has 5677, 81 m of length. A pavement design was made using the program BISAR 3.0 and a fatigue life study was made, also, in order to estimate the number of loads (in terms of heavy vehicles axle) to cause road’s failure . An alignment design was made for this project and a safety study was established in order to check if the available sight distance at curves respects the safety norms or not, by comparing it to the stopping sight distance. Different technical sheets are demonstrated and several cases are discussed in order to clarify the main design principles and underline the main hazardous cases to be avoided especially at intersection. This latter, its type’s choice depends on several factors in order to make the suitable design according to the environmental data. At this part of the road, the safety is a primordial point due to the high accident rate in this zone. For this reason, different safety aspects are discussed especially at roundabouts, signalized intersections, and also some other common intersection types. The design and the safety norms are taken with reference to AASHTO (American Association of State Highway and Transportation Officials), ACT (Transportation Association of Canada), and also according to Italian norms (Decreto Ministeriale delle Starde).

Investigation of using waste engine oil blended with reclaimed asphalt materials to improve pavement recyclability

With the increasing importance of conserving natural resources and moving toward sustainable practices, the aging transportation infrastructure can benefit from these ideas by improving their existing recycling practices. When an asphalt pavement needs to be replaced, the existing pavement is removed and ground up. This ground material, known as reclaimed asphalt pavement (RAP), is then added into new asphalt roads. However, since RAP was exposed to years of ultraviolet degradation and environmental weathering, the material has aged and cannot be used as a direct substitute for aggregate and binder in new asphalt pavements. One material that holds potential for restoring the aged asphalt binder to a usable state is waste engine oil. This research aims to study the feasibility of using waste engine oil as a recycling agent to improve the recyclability of pavements containing RAP. Testing was conducted in three phases, asphalt binder testing, advanced asphalt binder testing, and laboratory mixture testing. Asphalt binder testing consisted of dynamic shear rheometer and rotational viscometer testing on both unaged and aged binders containing waste engine oil and reclaimed asphalt binder (RAB). Fourier Transform Infrared Spectroscopy (FTIR) testing was carried out to on the asphalt binders blended with RAB and waste engine oil compare the structural indices indicative of aging. Lastly, sample asphalt samples containing waste engine oil and RAP were subjected to rutting testing and tensile strength ratio testing. These tests lend evidence to support the claim that waste engine oil can be used as a rejuvenating agent to chemically restore asphalt pavements containing RAP. Waste engine oil can reduce the stiffness and improve the low temperature properties of asphalt binders blended with RAB. Waste engine oil can also soften asphalt pavements without having a detrimental effect on the moisture susceptibility.

Numerical study on the curling and warping of hardened rigid pavement slabs

In-service hardened concrete pavement suffers from environmental loadings caused by curling and warping of the slab. Traditionally, these loadings are computed on the basis of treating the slab as an elastic material, and of evaluating separately the curling and warping components. This dissertation simulates temperature distribution and moisture distribution through the slabs by use of a developed numerical model that couples the heat transfer and moisture transport. The computation of environmental loadings treats the slab as an elastic-viscous material, which considers the relaxation behavior and Pickett effect of the concrete. The heat transfer model considers the impacts of solar radiation, wind speed, air temperature, pavement slab albedo, etc. on the pavement temperature distribution. This dissertation assesses the difference between documented models that aim to predict pavement temperature, highlighting their pros and cons. The moisture transport model is unique for the documented models; it mimics the wetting and drying events occurring at the slab surface. These events are estimated by a proposed statistical algorithm, which is verified by field rainfall data. Analysis of the predicted results examines on the roles of the local air RH (relative humidity), wind speed, rainy pattern in the moisture distribution through the slab. The findings reveal that seasonal air RH plays a decisive role on the slab‘s moisture distribution; but wind speed and its daily variation, daily RH variation, and seasonal rainfall pattern plays only a secondary role. This dissertation sheds light on the computation of environmental loadings that in-service pavement slabs suffer from. Analysis of the computed stresses centers on the stress relaxation near the surface, stress evolution after the curing ends, and the impact of construction season on the stress‘s magnitude. An unexpected finding is that the total environmental loadings at the cyclically-stable state divert from the thermal stresses. At such a state, the total stress at the daytime is roughly equal to the thermal stress; whereas the total stress during the nighttime is far greater than the thermal stress. An explanation for this phenomenon is that during the night hours, the decline of the slab‘s near-surface temperature leads to a drop of the near-surface RH. This RH drop results in contraction therein and develops additional tensile stresses. The dissertation thus argues that estimating the environmental loadings by solely computing the thermally-induced stresses may reach delusive results. It recommends that the total environmental loadings of in-service slabs should be estimated by a sophisticated model coupling both moisture component and temperature component.

Evaluation of the performance and cost-effectiveness of pavement sections containing open-graded base courses

Moisture induced distresses have been the prevalent distress type affecting the deterioration of both asphalt and concrete pavement sections. While various surface techniques have been employed over the years to minimize the ingress of moisture into the pavement structural sections, subsurface drainage components like open-graded base courses remain the best alternative in minimizing the time the pavement structural sections are exposed to saturated conditions. This research therefore focuses on assessing the performance and cost-effectiveness of pavement sections containing both treated and untreated open-graded aggregate base materials. Three common roadway aggregates comprising of two virgin aggregates and one recycled aggregate were investigated using four open-ended gradations and two binder types. Laboratory tests were conducted to determine the hydraulic, mechanical and durability characteristics of treated and untreated open-graded mixes made from these three aggregate types. Results of the experimental program show that for the same gradation and mix design types, limestone samples have the greatest drainage capacity, stability to traffic loads and resistance to degradation from environmental conditions like freeze-thaw. However, depending on the gradation and mix design used, all three aggregate types namely limestone, natural gravel and recycled concrete can meet the minimum coefficient of hydraulic conductivity required for good drainage in most pavements. Tests results for both asphalt and cement treated open-graded samples indicate that a percent air void content within the range of 15-25 will produce a treated open-graded base course with sufficient drainage capacity and also long term stability under both traffic and environmental loads. Using the new Mechanistic and Empirical Design Guide software, computer simulations of pavement performance were conducted on pavement sections containing these open-graded base aggregate base materials to determine how the MEPDG predicted pavement performance is sensitive to drainage. Using three truck traffic levels and four climatic regions, results of the computer simulations indicate that the predicted performance was not sensitive to the drainage characteristics of the open-graded base course. Based on the result of the MEPDG predicted pavement performance, the cost-effectiveness of the pavement sections with open-graded base was computed on the assumption that the increase service life experienced by these sections was attributed to the positive effects of subsurface drainage. The two cost analyses used gave two contrasting results with the one indicating that the inclusion of open-graded base courses can lead to substantial savings.

Estimating greenhouse gas emissions of highway construction and rehabilitation to support pavement life cycle assessment

Highway infrastructure plays a significant role in society. The building and upkeep of America’s highways provide society the necessary means of transportation for goods and services needed to develop as a nation. However, as a result of economic and social development, vast amounts of greenhouse gas emissions (GHG) are emitted into the atmosphere contributing to global climate change. In recognizing this, future policies may mandate the monitoring of GHG emissions from public agencies and private industries in order to reduce the effects of global climate change. To effectively reduce these emissions, there must be methods that agencies can use to quantify the GHG emissions associated with constructing and maintaining the nation’s highway infrastructure. Current methods for assessing the impacts of highway infrastructure include methodologies that look at the economic impacts (costs) of constructing and maintaining highway infrastructure over its life cycle. This is known as Life Cycle Cost Analysis (LCCA). With the recognition of global climate change, transportation agencies and contractors are also investigating the environmental impacts that are associated with highway infrastructure construction and rehabilitation. A common tool in doing so is the use of Life Cycle Assessment (LCA). Traditionally, LCA is used to assess the environmental impacts of products or processes. LCA is an emerging concept in highway infrastructure assessment and is now being implemented and applied to transportation systems. This research focuses on life cycle GHG emissions associated with the construction and rehabilitation of highway infrastructure using a LCA approach. Life cycle phases of the highway section include; the material acquisition and extraction, construction and rehabilitation, and service phases. Departing from traditional approaches that tend to use LCA as a way to compare alternative pavement materials or designs based on estimated inventories, this research proposes a shift to a context sensitive process-based approach that uses actual observed construction and performance data to calculate greenhouse gas emissions associated with highway construction and rehabilitation. The goal is to support strategies that reduce long-term environmental impacts. Ultimately, this thesis outlines techniques that can be used to assess GHG emissions associated with construction and rehabilitation operations to support the overall pavement LCA.

Reflectivity and durability of epoxy pavement markings. Interim report.

Federal Highway Administration, Office of Research, Development and Technology, Washington, D.C.

Durable pavement marking materials: summary report of 1981 workshops.

Federal Highway Administration, Implementation Division, Washington, D.C.

Calibration services for pavement survey equipment. Executive summary. Final report.

Federal Highway Administration, Office of Engineering and Highway Operations Research and Development, Washington, D.C.

Roadway lighting handbook, addendum to chapter six: designing the lighting system using pavement luminance. Final report.

Federal Highway Administration, Implementation Division, Washington, D.C.

Raised pavement markers at hazardous locations. Final report.

Mode of access: Internet.

Evaluation of raised snowplowable pavement markers. Final report.

Federal Highway Administration, Office of Research, Washington, D.C.

Procedures for controlling the effect of increased tire pressure on asphalt concrete pavement damage. Final report.

Oregon Department of Transportation, Salem

Snowplowable raised reflective pavement markers at hazardous locations in New Jersey.

Federal Highway Administration, Implementation Division, Washington, D.C.

Optimal placement of reflective pavement markers. Final report.

Ohio Department of Transportation, Columbus