Sustainable Pavement Management Research Articles

Integrating Tensometer Measurements, Elastic Half-Space Modeling, and Long-Term Pavement Performance Data into a Mechanistic–Empirical Pavement Performance Model

Pavement performance models (PPMs) are utilized to predict pavement network conditions which is an essential part of any sustainable pavement management system (PMS). The reliability of a PMS and its outputs is proportional to the reliability of the PPM used. This article describes a mechanistic–empirical pavement performance model based on pavement response parameters—strains calculated in the pavement layers measured by tensometers embedded in the pavement surface and verified by calculations in the elastic half-space model and supplemented by empirical data from long-term pavement performance monitoring and accelerated pavement testing. Hence, the herein described PPM combines pavement serviceability evaluation, pavement bearing capacity, and the physico-mechanistic properties of paving materials. The analytical methods which were used to ascertain the physico-mechanistic characteristics, the material fatigue degradation model, and the surface degradation, unevenness in particular, are described. A comparison of the empirical PPM created in the last century used by the national road administrator to this day and the newly created PPM is presented. The comparison shows the difference in the calculated socio-economic benefits and subsequent cost–benefit analysis results. The comparison shows that the use of the old PPM may have produced false economic evaluation results that have led to poor decision making, partially explaining the unsustainable trend of road network management in our country.

Identifying environmentally sustainable pavement management strategies via deep reinforcement learning

Pavement life cycle assessments (LCAs) enable decision-makers to evaluate the environmental impact of alternative maintenance, rehabilitation, and reconstruction strategies. This paper explores the viability of deep reinforcement learning (DRL), a framework that enables agents to learn optimal actions within a given situation, to identify environmentally benign pavement management strategies. More specifically, this study utilizes proximal-policy optimization (PPO), a subtype of DRL algorithms, to identify a management strategy that minimizes the expected global warming impact of a pavement facility over its lifecycle. Through an urban Interstate case study, this paper shows that the proposed PPO algorithm identifies management strategies that are anticipated to reduce the expected global warming impact of a pavement facility over its planning horizon by 16 percent relative to traditional practice. Furthermore, the PPO algorithm is able to identify this management strategy in only 25 learning iterations, which is in stark comparison to Q-learning, a common reinforcement learning algorithm, that requires 70,000 learning iterations. The results of this work highlight the viability of DRL to integrate within complex LCA models to determine environmentally sustainable pavement management strategies.

Developing a Sustainable Pavement Management Plan: Economics, Environment, and Social Equity

Developing a Sustainable Pavement Management Plan: Economics, Environment, and Social Equity

Bituminous pavement sustainability improvement strategies

Transportation systems have enormous challenges in terms of sustainability since they deal with issues like economic, environmental, and social factors, and pavement sustainability is unavoidably one of these problems. This study investigates pavements' sustainability potential, and in doing so, it looks at both global practices and personal experiences. This research investigates the long-term viability of pavements. Some of the topics covered in this course are: Recycled Concrete, Recycled Asphalt Pavement, Bio-binders of asphalt, asphalt cement, warm mix asphalt, tack coat, rubberized asphalt (RA), polymer modified asphalt (PMA), and sustainability in pavement design. According to the findings, research is needed to provide environmental sustainability training, including preservation and maintenance solutions. Carbon sequestration and resource regeneration are environmental sustainability elements that need to be considered when selecting treatment options for pavement preservation. Recycled or alternative materials must be found for pavement preservation and maintenance techniques. Finally, research is urgently needed to assess the environmental advantages of asphalt crack sealing. It is thus imperative that any new studies on pavement incorporate sustainable pavement management components.

Cost-effectiveness evaluation of pavement maintenance treatments using multiple regression and life-cycle cost analysis

The present study compared the effectiveness and cost-effectiveness of four pavement treatments, including hot in-place recycling, milling and filling, thin HMA overlay and microsurfacing. The multiple regression analysis was employed to investigate the effectiveness of treatments and the effect of pretreatment rutting severity and traffic conditions on maintenance effectiveness. The rutting depth (RD) was selected as a performance indicator. The reduction of RD degradation rate and increase in average RD over monitoring period were used as measures of treatment effectiveness. Life-cycle cost analysis was performed to evaluate the treatment cost-effectiveness over a 50-year analysis period. Results indicate that the hot in-place recycling possesses the highest effectiveness and cost-effectiveness. Using reclaimed asphalt pavement (RAP) at appropriate maintenance timing substantially benefits for restoring the rutting resistance of asphalt pavement. These findings provide project agencies with quantitative evidence to support the establishment of the rutting-based maintenance decision-making system and the utilization of RAP in the sustainable pavement management strategies.

Modeling life-cycle social assessment in sustainable pavement management at project level

PURPOSE: Currently, modeling of social impacts in sustainable pavement management (SPM) is still in the infant stage, which generally causes significant social impacts and triggers several social hotspot issues. Therefore, this paper aims to evaluate the social impacts on pavement over its main life-cycle stages. METHODS: To achieve this goal, the UNEP/SETAC guidelines were employed to develop the social life-cycle assessment (S-LCA) framework for pavement. Stakeholders, subcategories, and part of social indicators were identified from previous studies, and the other part of social indicators were particularly developed based on pavement characteristics. In particular, direct and indirect social indicators were both used, which evaluate social impacts directly and indirectly, respectively. Moreover, site-specific data were extensively collected and verified using cross-checking by multiple data collection approaches and sources, while generic data were adopted as reference values. Subsequently, the existing approaches of assigning scores were applied for direct and indirect social indicators, and the weights were determined using the analytic hierarchy process method. A final score was aggregated to evaluate the social impacts of pavement. In addition, a case study of traditional hot-mix asphalt (HMA) in China was applied and the social hotspots were identified for the local pavement sector. RESULTS AND DISCUSSION: This study involved four pavement life-cycle stages of raw materials and production, construction, use, and maintenance, along with 4 stakeholders, 12 subcategories, and 16 social indicators. In particular, the use stage was addressed due to its significant social impacts during the long service life for pavement. Moreover, the subcategories and social indicators associated with worker category were most integrated, and the consumer was incorporated. In the case study of HMA pavement, the use stage contributed the greatest positive social impacts, while local community was identified as an important stakeholder, followed by worker. In addition, the subcategories of health and safety received the top three scores. However, gender discrimination was a significant social problem in the local pavement sector as indicated by the lowest score of equal opportunities subcategory. CONCLUSION: The proposed S-LCA framework is effective in evaluating the social impacts of pavement related to affected stakeholders during its main life-cycle stages. This study lays the foundation for the development of S-LCA framework for pavement, and the identified and proposed social indicators not only are used to evaluate the comprehensive social impacts of pavement, but also are suitable for other construction projects.

Laboratory Compaction Study and Mechanical Performance Assessment of Half-Warm Mix Recycled Asphalt Mixtures Containing 100% RAP.

The use of low-carbon and energy-efficient paving technologies is gaining worldwide acceptance in recent years as a means to encourage commitment towards more sustainable pavement management practices. However, there still remain some technical gaps regarding mix design procedures for the half-warm mix asphalt (HWMA) mixtures’ preparation and characterization in the laboratory. To this end, three different laboratory compaction methods (e.g., static load, Marshall impactor, and gyratory compactor) were selected and put into assessment to define the most suitable compaction test method for half-warm mix recycled asphalt (HWMRA) mixtures with 100% reclaimed asphalt pavement (RAP). Posteriorly, the effect of four-accelerated curing treatments (0, 24, 48, and 72 h) on the mixtures’ mechanical performance was investigated. Then, advanced mechanical characterization of the mixture performance was conducted to quantify the indirect tensile strength (ITS), stiffness modulus, rutting, and four-point bending (4PB) fatigue test. Thus, based on the authors’ findings, the HWMRA mixtures with 100% RAP and emulsified bitumen exhibited proper volumetric (e.g., air voids and density) and mechanical behavior in terms of moisture damage, ITS, stiffness modulus, rutting, and fatigue cracking. These findings encourage greater confidence in promoting the use of these sustainable asphalt mixes for their use in road pavements or urban streets.

A comparative study of monitoring methods in sustainable pavement management system

Pavement management systems (PMS) have been receiving increasing attention in the attempt to ensure that roads are always in good condition and serving its purpose. Appropriate PMS must be implemented to gather valid and reliable pavement data. Previous studies which attempted to identify methods for monitoring pavements were limited by constraints such as cost, time, safety, data accuracy and sustainability. This study was conducted to review some of the pavement monitoring models introduced in previous studies. After completing a literature review, three models, i.e. manual survey, smart sensor, and optical image processing, were selected for a comparative study to determine which of these models is the most effective model in terms of cost, time, safety, accuracy and sustainability. A data quality guideline was modified to produce a rating system for ranking the models from the worst to the best. The results of this study shows that smart sensor has the highest score in the radar chart, and hence is the best model. In conclusion, the findings of this study could provide a guideline for the government and private sectors in determining the most effective pavement monitoring model to be used in their sustainable PMS strategy despite the constraining factors.

Developing a Sustainable Pavement Management Plan: Tradeoffs in Road Condition, User Costs, and Greenhouse Gas Emissions

Developing a Sustainable Pavement Management Plan: Tradeoffs in Road Condition, User Costs, and Greenhouse Gas Emissions

Quantifying Environmental Costs for Sustainable Pavement Management

We quantify the effect of Ontario's provincial transportation infrastructure decisions on multipollutant exposures, impacts, and life-cycle costs. A variety of evidence shows that roadway construction and maintenance affect human health and climate change via emissions of air pollutants and greenhouse gases. With recent policy shifts, provincial transportation decision-makers are focused on the role of roadway design and maintenance on these environmental exposures; however, they lack appropriate tools to incorporate them into decisions. Here, we present a decision-making tool that quantifies the health, environmental, and economic impacts of construction, maintenance, and rehabilitation of roads and highways. We examine various pavement design and management approaches, including standard practices, and innovations to processes and materials. We estimate multipollutant emissions, including (CO2, NOx, SO2, PM2.5, CO). We review literature that connects these exposures to health and economic impacts directly through marginal damage estimates. Current literature estimates for the cost of emitting a single metric tonne of fine particulate matter range between $600 and $50,000 (2010 CAD) depending on the impacts considered and the cost measures used. Preliminary findings for environmental costs of emissions from new-construction of a double-lane, one-kilometre road range between $300 to $50,00 for asphalt roads and $3000 to $400,00 (2010 CAD) for concrete roads. In this research, we expand on these findings and quantify contributions of uncertainty from exposures, exposure-response, and economic impacts. These findings allow infrastructure managers to account for health-related impacts of environmental exposures, including air pollutants and greenhouse gases, and thus to design more sustainable solutions.

Selecting Network-Level Project Sections for Sustainable Pavement Management in Texas

In recent years, the increasing gap between available funding and preservation needs has influenced district pavement engineers to select and prioritize projects to effectively use funding. However, currently, projects are often selected after an informal assessment, based on local conditions and local district engineers’ experience, in the absence of a statewide systematic process. The primary objective of this study is to determine network-level project sections for effective sustainable pavement management using logistic regression analysis. A large volume of inventory data, documented using pavement-management information systems (PMIS), was used to develop the logistic regression (LR) model for selecting candidate sections. The LR model was subsequently validated using a single 50/50 split sample method. The findings of this study will assist the Austin, Texas, USA district to select and evaluate candidate projects. Furthermore, the study will eventually contribute to improved efficiency in project selection and prioritization by reducing not only the amount of time necessary to review the district PMIS data to identify project candidates, but also the potential for human error.

A multi-objective optimisation approach for sustainable pavement management

Addressing the multidimensional challenges involved in advancing the sustainability of pavement systems requires the development of optimisation-based decision support system (DSS) for pavement management with the capability to identify optimally sustainable pavement maintenance and rehabilitations (M&R) strategies. The main objective of this research work is to develop a multi-objective optimisation framework that hosts a comprehensive and integrated pavement life cycle costs–life cycle assessment model that covers the pavement’s whole life cycle, from the extraction and production of materials to construction and maintenance, transportation of materials, work-zone traffic management, usage and end-of-life. The capability of the proposed DSS is analysed in a case study aiming at investigating, from a full life cycle perspective, the extent to which a number of pavement engineering solutions are efficient in improving the environmental and economic aspects of pavement sustainability, when applied in the management of a road pavement section. Multiple bi-objective optimisation analyses considering accordingly agency costs, user costs and greenhouse gas emissions were conducted based on a multi-objective genetic algorithm. Pareto fronts were obtained for each analysis, originating a set of non-dominated maintenance and rehabilitation solutions. Posteriorly, a multi-criteria decision analysis method was used to find the best compromise solution for pavement management.

Sustainable Pavement Management System in Urban Areas Considering the Vehicle Operating Costs

Urban roads constitute most of the existing roads and they are directly managed by small administrations. Normally, these small administrations do not have sufficient funds or sufficient qualified personnel to carry out this task. This paper deals with an easy-implementation Pavement Management System (PMS) to develop strategies to maintain, preserve and rehabilitate urban roads. The proposed method includes the creation of the road network inventory, the visual surveys of the pavement and the evaluation of its condition by the Pavement Condition Index (PCI). The method intends to give a valid tool to road managers to compare alternative maintenance strategies and perform the priority analysis on the network. With this aim, the procedure assesses the Vehicle Operating Costs (VOC) by a written regression between PCI and International Roughness Index (IRI). The proposed method has several advantages because it can be easily adapted to various situations and it does not require a large amount of time and money for its implementation.

Environmental and economic assessment of pavement construction and management practices for enhancing pavement sustainability

Stakeholders in the pavement sector have been seeking new engineering solutions to move towards more sustainable pavement management practices. The general approaches for improving pavement sustainability include, among others, reducing virgin binder and virgin aggregate content in HMA and WMA mixtures, reducing energy consumed and emissions generated in mixtures production, applying in-place recycling techniques, and implementing preventive treatments. In this study, a comprehensive and integrated pavement life cycle costing- life cycle assessment model was developed to investigate, from a full life cycle perspective, the extent to which several pavement engineering solutions, namely hot in-plant recycling mixtures, WMA, cold central plant recycling and preventive treatments, are efficient in improving the environmental and economic dimensions of pavement infrastructure sustainability, when applied either separately or in combination, in the construction and management of a road pavement section located in Virginia, USA. Furthermore, in order to determine the preference order of alternative scenarios, a multicriteria decision analysis method was applied. The results showed that the implementation of a recycling-based maintenance and rehabilitation strategy where the asphalt mixtures are of type hot-mix asphalt containing 30% RAP, best suits the multidimensional and conflicting interests of decision-makers. This outcome was found to be robust even when different design and performance scenarios of the mixtures and type of treatments are considered.

Sustainable Development Factors in Pavement Life-Cycle: Highway/Airport Review

Sustainability has gained as much importance as management in business. Sustainable pavement development as a business practice should involve making evaluations according to the triple bottom line in the pavement life-cycle. Despite the current approaches to evaluating the social as well as economic and environmental feasibility of pavement projects (involving highway and airport infrastructure), there has recently been a lack of consensus on a methodology to guarantee sustainability upon assessment and analysis during the pavement life-cycle. As sustainability is a complex issue, this study intends to further explore sustainability and elaborate on its meaning. The second step involves a general depiction of the major sustainability appraisal tools, namely cost-benefit analysis, life-cycle cost analysis, life-cycle assessment, multi-criteria decision-making, environmental impact assessment and social life-cycle assessment, and an explanation of their cons and pros. Subsequently, the article addresses the application of an organized methodology to highlight the main factors or concepts that should be applied in sustainable pavement development and, more specifically, in sustainable pavement management. In the final step, research recommendations toward sustainability are given. This study is aimed to assist decision-makers in pavement management to plan sustainability frameworks in accordance with probable boundaries and restrictions.

Requirements of a Sustainable Pavement Management System for Tanzania

Requirements of a Sustainable Pavement Management System for Tanzania