Many highway facilities experience deterioration due to high traffic volumes and a service life that has been extended beyond facility design life. The 75th and 76th Texas Legislatures passed bills allowing trucks of gross vehicle weights (GVW) up to 125,000 lbs to routinely use a route in south Texas. Since the Texas Department of Transportation (Tx DOT) is concerned about the impact of overweight truck traffic (OTT) on its highways, there is a need to establish how the impact of this OTT on Texas roads will be incorporated into a long-term strategy for identifying and developing solutions to this problem. In this study was investigated the effects of overweight truck traffic on a permitted truck route in the city of Brownsville. This route proceeds from the Veterans International Bridge to the Port of Brownsville via US77, SH4 and SH48 (SH 4/48). The objective of this study is to establish the impact of this heavy loads on the pavement structure through nondestructive testing. The problem increased in severity due to the increased flow of trade from the Port of Brownsville to Mexico, thus the expecting deterioration on the routes is mainly along the southbound lanes K6 and K7. To accomplish this objective was conducted two nondestuctive testing as GPR and FWD test. The K6 and K7 lanes were divided on 56 and 50 FWD stations, respectively. In addition, it was taken AC core samples to be tested with frequency sweep test. All these information assisted to analyze: the route profile, layers thickness, static and dynamic backcalculated AC moduli, dynamic (complex) modulus from laboratory testing, creep compliance parameters from the laboratory testing and dynamic analysis, and corrected AC moduli by temperature using three differents equations. In addition, it was analyzed the effect of the cumulative 18-kip Equivalent Single Axle (ESAL) in both K6 and K7 lanes. The results from the first analysis provide evidence of damage in the K6 lane; however, more significant results were found in the traffic analysis. This study confirms that because of greater amount of truck traffic (OTT) travels on K6 it has lesser AC moduli than the K7 lane.

Economic Input Output Life Cycle Assessment (EIO-LCA) provides economic transactions, environmental emissions, and energy use throughout a product's life cycle based on a dollar amount of the product. A custom EIO-LCA model was conducted to compare three major rigid pavements of Jointed Plain Concrete Pavement (JPCP), Jointed Reinforced Concrete Pavement (JRCP), and Continuously Reinforced Concrete Pavement (CRCP) within the perspective of economic transactions, greenhouse gases, energy use, hazardous waste, toxic releases, water withdrawals, and transportation movements. The analysis results indicate that CRCP be the most cost-efficient and sustainable choice among the selected rigid pavement alternatives as it requires the lowest life-cycle cost and has the least unfavorable impact on environment when compared to the JPCP and JRCP. Potential improvements could be investigated for the processes of cement manufacturing, power generation and supply, ready-mix concrete manufacturing, and truck transportation because the EIO-LCA results reveal that they are the top sectors contributing to the energy use and greenhouse gases emissions. The results also indicate that some sectors such as storage of materials, landfills, and soil waste management should be taken into account in order to reduce toxic releases. Moreover, the utilization of local human resources as well as raw materials would help to minimize transportation movement. This study shows that EIO-LCA is a valuable tool and presents how it can help decision-makers make a better-informed decision when there are multiple options. In future studies, uncertainties related to location and time should be captured to generalize the results of the EIO-LCA with more sophisticated data collection and stratification protocol.

This study aimed at investigating the current practices and methods adopted by roads agencies around the world with regard to collection, analysis and utilization of the data elements pertaining to the main pavement condition indicators in pavement management systems (PMS). It also aimed at identifying the main predictors associated with each condition indicator and the factors that govern pavement structural and functional performance. Development of a new performance index that incorporates parameters or measures related to the main condition indicators (surface defects, roughness, deflection and skid resistance) and establishing the weight to be assigned to each indicator based on the relative impact on pavement condition was also one of the main objectives of this study. Thousands of pavement sections were subjected to thorough testing and inspection over the last few years to collect data pertaining to the main condition indicators. The collected data encompass visual distress survey, deflection measurements, roughness and skid resistance measurements. Collection of various condition indicators was accomplished according to well known international standards. The collected data were processed, tabulated and analyzed for the purpose of development of performance models and to prove certain theories or good practices. / Advanced tools and machines were utilized to collect these data with a high degree of accuracy. The Falling Weight Deflectometer (FWD) was used to collect deflection data for structural analysis. Two Non-contact laser roughness measuring devices mounted on vehicles were heavily used for collecting roughness, texture, and rutting data. Distress data were collected using a manual procedure adopted and standardized at the Pavement Management System Unit of Dubai Emirate. Powerful engineering and statistical softwares were used in the analysis for the purpose of processing the data, back calculating the main parameters pertaining to pavement response, establishing the correlation matrices between various dependent variables and their predictors, and finally, applying linear and non linear regression analysis to develop reliable and predictable deterioration models for the uses of pavement management system. The analysis procedure was supplemented by a vast literature review for the up to date information along within deep investigations and verifications for some of the current practices, theories and models used in pavement design and pavement evaluation with more emphasis on the inherent drawbacks associated to these models and procedures. The study confirmed that pavement condition deterioration and performance can be best predicted and evaluated based on four main condition indicators; First, surface distress to assess the physical condition of the pavements and detect the inherent problems and defects caused by various factors affecting pavement performance. Second; roughness measurements to evaluate the riding quality of the pavement. / Third; deflection to calculate pavement response (stress and strains) and to assess pavement structural capacity and calculating the remaining life, and finally, skid resistance measurement to assess the level of safety and surface texture properties. Thorough study and investigation of the physical condition indicators and the associated parameters, confirmed that pavement distress data are vital elements in each pavement management system. Distress data can be used effectively to identify the main problems associated with pavement performance, causes of deterioration, maintenance measures needed to prevent the acceleration of the distress, the rehabilitation schemes needed to improve the pavement condition and finally to prepare maintenance work programs and to estimate the annual maintenance needs under an open or limited budget. Alligator cracking was found to have the heaviest impact on pavement condition. Distress density, probable causes of deterioration and distress propagation rate are the required parameters in PMS. Roughness was found to have a basic influence on pavement condition and the type of selected treatment. The use of Roughness data in terms of International Roughness Index (IRI) can be optimized in PMS by using this indicator in the following forms: / Roughness, as an objective measure, can be used as a good performance predictor of the current riding quality of pavements in service and reflects the inherent imperfections and built-in irregularities embodied in the road pavement surface. Roughness measurement can be used as a reference to establish construction specifications and provides through the PMS system an organized feedback approach to correct the persistent design deficiencies detected after road construction. Roughness can be used effectively in the planning process for maintenance works and to select the candidate sections through calculating the functional remaining life based on the estimated terminal value using Roughness-Age, Roughness-ESAL, and Roughness-PSI models. Lane–IRI along with the Difference between the left and right wheel IRI values, termed as “ Yaw” are the most suitable forms to be used in PMS to report about roughness characteristics. Yaw term can be used effectively to report or feed back about geometric imperfections that exist on the road surface such as improper cross slope, shoving and the probable drainage problems. The roughness cumulative distribution curves can be used as a planning tool in PMS to report at the network level. These curves indicate the network health and the required funding at different level of risks, so proactive measures can be taken and the required budgets can be made available. / Deflection data were found to form a basic component of the PMS. It was found that these data can be used at both network and project levels. Direct deflection measurements were found Not to be the ideal form to report about structural capacity at the network level. It is rather can be used at project level to detect weak spots and critical pavements layers. At the network level, the back calculated parameters from deflection basin such as Pavement Modulus (Ep), Asphalt and Pavement Curvature (CUR), Cross Sectional Area and the other deflection basin characteristics are much more appropriate for reporting about pavement structural conditions and calculating the structural remaining life in PMS. The design deflection and curvature that characterize the pavement have been found to be calculated based on the mean along with the two times the standard deviation of the measured data. The Effective Structural Number (SNeff) was found to have good correlations with the Total Pavement Thickness (Ht), the value of the deflection measured at the center of the loading plate ( D0 ) and the difference between D0 and the deflection measured at 450mm from the center of the loading plate ( D0 - D450 ). The first two variables were found to account for more than 92% of the structural capacity prediction model. / Traffic variable in terms of the accumulated standard repetitions (ESAL) was found to account for more than 60% of the deflection model predictability. Other variables such as E value, asphalt and base layer thicknesses can improve the predictability of the model if included. The concept of the relative value of effective pavement modulus to the original pavement modulus (Eeff/E0) was found to gives a reliable representation about the exhausted and the remaining life of the in-service pavement structure. The study showed that the pavement is reported to be structurally failed, when the effective asphalt or pavement modulus is about 20 - 35 % of its original design value which is equal to the modulus of the unbound material. It was also found that when the area of the fatigue cracking and the patching distresses exceeds 17% of the total pavement section area, or the depth of rutting is more than 15mm, the pavement is reported to be structurally failed and major rehabilitation or reconstruction should be applied. Skid resistance can be reported in the form of International Friction Index (IFI), as a well defined universal index, along with other two numbers; F60 Friction (Microtexture) related number measured at 60 km/h velocity and Macrotexture related number and Vp, which constitute the IFI index can be used in Pavement management system applications to report about skid resistance characteristics and the network level of safety. These three figures can be used to report about pavement condition, accidents, airports operations, and maintenance management surveys. / In this study, new methods and models were developed and suggested to be used in PMS as an alternative to the current available methods which were found to be impractical in certain cases. Finally, further research efforts are recommended to explore the uses of other parameters in particular those related to deflection basin analysis, cross sectional area, curvature, and pavement moduli. Skid resistance testing and reporting method should be subjected to further research works for the purpose of standardizing reporting methods, identifying the relative impact of main predictors i.e. megatexture, macrotexture and microtexture components and to develop performance models.

Wet-pavement friction is a public concern because of its direct relation to highway safety. Both short- and long-term seasonal variations have been observed in friction measurements. These variations have been attributed to different factors, such as traffic, rainfall, and temperature. Since both the tire rubber and the HMA pavement surface are viscoelastic materials, which are physically sensitive to temperature changes, temperature should affect the measured frictional properties. Although several researchers have attempted to explain and quantify the effect of temperature on pavement friction, it remains to be fully understood. The objective of this research was to quantify the effect of pavement surface temperature on the frictional properties of the pavement-tire interface. To accomplish this, tests conducted on seven different wearing surfaces at the Virginia Smart Road under different climatic conditions were analyzed. Due to the short duration of this study and the low traffic at the facility, only short-term effects of temperature on pavement friction were investigated. To accomplish the predefined objective, skid test data from both ribbed and smooth tires were collected over two and a half years (from January 2000 to August 2002) and then analyzed. Six sets of tests were conducted under different environmental conditions. The pavement and air temperatures during each test were obtained using thermocouples located directly under the wearing course (38mm below the surface) and close to the pavement surface, respectively. Regression analyses were conducted to determine the effect of pavement temperature on the measured skid number at different speeds, as well as on friction model parameters. The main conclusion of this investigation is that pavement temperature has a significant effect on pavement frictional measurements and on the sensitivity of the measurements to the test speed. Both the skid number at zero speed (SN0) and the percent normalized gradient (PNG) tend to decrease with increased pavement temperature. This results in the pavement temperature on the measured skid number being dependent on the testing speed. For the standard wearing surface mixes studied at low speed (lower than 32 km/hr), pavement friction tends to decrease with increased pavement temperature. At high speed, the effect is reverted and pavement friction tends to increase with increased pavement temperature. Temperature-dependent friction versus speed models were established for one of the mixes studied. These models can be used to define temperature correction factors. / Master of Science

The City of Saskatoon (COS) manages diverse road infrastructure assets. Given the present day challenges of structurally upgrading in-service road infrastructure assets in diverse field state conditions, there is a need to incorporate new innovative materials, changing field state conditions, and mechanistic design methods in sustainable road rehabilitation decision making. The COS is faced with challenges including rising material and labour costs, budget shortfalls, depleting virgin aggregate sources in close proximity to the COS, and an increase in stockpiled asphalt and concrete rubble materials due to transportation infrastructure renewal. As a result of the COS impact crushing program, a need to determine the design and performance properties of using recycled reclaimed asphalt concrete (RAP) rubble materials in urban pavement structures was established. RAP materials had never been used as a structural base layer in COS pavement structures because no material characterization had been conducted and there was no performance information with regards to their structural behaviour and field performance available. Other jurisdictions documented benefits of using recycled RAP in road structure include: reduced demand on depleting aggregate sources; reduced energy consumption; diversion of stockpiled RAP materials from landfills; and reduced overall handling and disposal costs. Given the amount of crushed RAP material available to the COS, it was determined there are potential benefits to implementing the use of recycled crushed RAP rubble in pavement structures, leading to the implementation of the “Green Street” Infrastructure Program. The findings of this research indicate that RAP materials have improved mechanistic properties compared to conventional granular materials; therefore, RAP materials can be used as a base layer in a road structure. This research indicates that cement stabilization and cement with a slow setting (SS-1) emulsion stabilization improved the moisture susceptibility of well graded (GW) and open graded base course (OGBC) RAP materials. These findings demonstrated that RAP materials stabilized with cement and/or SS-1 emulsion can be used as a base layer in a pavement structure. This research also found that the standard Proctor compaction method is not applicable for RAP materials to quantify moisture-density behaviour under compaction, due to the bound-nature of RAP aggregates, which are composed of asphalt and aggregate. California bearing ratio (CBR) values of Proctor-compacted RAP specimens did not accurately reflect field performance observations. As part of the COS “Green Street” Infrastructure Program, two test sections using crushed GW RAP rubble materials as a base layer were constructed as part of this research and include Marquis Drive (eastbound lanes from Thatcher Avenue to Idylwyld Drive) and 8th Street East (westbound lanes from Boychuk Drive west 0.540 kilometers). Test sections were constructed by the City of Saskatoon with conventional construction equipment and showed structural improvement in structural performance and visual distresses. Using RAP materials as a base layer was economically feasible because the RAP material cost less than conventional virgin aggregate base materials. This research demonstrates that processed and crushed RAP rubble materials are technically feasible to be used as a structural base layer in a recycled pavement structural system for urban road rehabilitation systems, and provide economic benefits over conventional granular base materials.

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