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As an advanced technology for pavement crack maintenance with high automation level, high precision and high efficiency, 3D asphalt printing technology can effectively improve worker safety and ensure the stability of maintenance quality. In order to optimize the printing parameters of rubber modified 3D printed asphalt (R-3DPA), a three-axis asphalt 3D printer was developed in this study through the design and selection of each component, and it was used for the 3D printing of R-3DPA strips, layers, and structures. Based on the comparison of continuity, uniformity, and width of R-3DPA strips, the recommended extrusion nozzle diameter, printing temperature, and printing speed parameter combinations were superiorly selected. According to the analysis of filling degree, width error and thickness of R-3DPA layers, the optimal printing strip width was recommended. Through the evaluation of integrity, surface characteristics and accuracy of R-3DPA structures, the suitable printing layer thickness was determined. The test results showed that the three-axis asphalt 3D printer can be used to measure the parameters of R-3DPA, and the printing accuracy and scale meet the requirements. The recommended parameters for R-3DPA are an extrusion nozzle diameter of 2 mm, a printing temperature of 180 °C, a printing speed of 20 mm/s, a printing strip width of 2.25 mm and a printing layer thickness of 0.4 mm, resulting in structures with good integrity and precision. • Optimize the printing parameters of R-3DPA. • Develop a three-axis asphalt 3D printer. • Recommend equipment parameters combinations of 3D printer. • Obtain the printing parameters of R-3DPA in pavement maintenance. [ABSTRACT FROM AUTHOR]

Transportation agencies routinely make repair decisions in numerous contexts which include the timing of different repair treatments over an extended period. The timing policy may be characterized either by a standalone manner that maximizes the outcome or utility of individual treatments at a given time, or by a holistic manner that maximizes the utility of all treatments together within a given horizon period. This study begins with a hypothesis that the effect of the sum of treatment prescriptions may be different from the sum of the effect of individual treatment prescriptions. The paper discusses separate practical applications where each of these two situations is pertinent. The study is based on the use of surface roughness as the indicator of pavement performance, and therefore, the framework includes the development of treatment-specific treatment performance jump and performance loss models in terms of roughness. The framework also includes identification of the optimal roughness thresholds for each pavement treatment as a standalone activity, followed by a determination of the thresholds for each treatment from a holistic standpoint. The latter involves the establishment of an optimal repair schedule over the pavement life cycle and recording the resulting roughness thresholds at which each treatment is recommended for application within the optimal schedule. Then the paper presents a case study to demonstrate application of the framework, and to compare the optimal-schedule thresholds versus the stand-alone thresholds. The case study involved fourteen treatment types, two surface material types (rigid and flexible) and three road functional classes. The results suggest that in this context of highway management, the optimal triggers associated with individual standalone repair treatments are not necessarily the same (and yield inferior outcomes) compared to the application thresholds of those treatments when they are considered within an optimized life-cycle schedule. The results can provide guidance to agencies as they examine or update their current roughness thresholds for each standard treatment and their long-term condition-based or time-based repair schedules. The paper's framework and results can also help agencies assess the consequences of deviations from a repair timing policy (delayed or hastened applications) due to lack of funds and other causes. [ABSTRACT FROM AUTHOR]

With the continuous expansion of highway construction scale, a complex road network can be divided into multiple subnetworks in accordance with any criteria, such as highway class, traffic volume, natural zoning, or administrative subdivision. To realize the targeted maintenance and local–whole optimization of a road network, this study proposes a new type of optimization model for road network maintenance decisions based on the idea of a bi-level programming model. The model fully considers the heterogeneity of a subnetwork, adopts different maintenance standards for targeted maintenance, establishes a whole network maintenance fund allocation model and a subnetwork unit maintenance decision-making (DM) model, and obtains the optimal maintenance scheme through the iterative calculation of a genetic algorithm. Finally, the model is applied to the maintenance DM of a highway network in Zhejiang Province and compared with the traditional DM model without subnetworks. Results show that the model developed in this study can better solve the maintenance DM problem of large-scale complex road networks and achieve the targeted maintenance scheme under limited maintenance funds. Hence, this model can help the sustainable development of road network maintenance. [Display omitted] • Constructed a maintenance decision optimization model for complex road networks. • Subnetwork division based on road network characteristics. • The model enables local-global optimization of road network maintenance. [ABSTRACT FROM AUTHOR]

Highlights • Investigate dependence of overlay field cracking performance on overlay thickness. • Investigate dependence of overlay field cracking performance on fracture energy. • Propose a new performance parameter for reflective cracking performance evaluation. • Propose thresholds for selection of overlay thicknesses and material types. Abstract This study investigates the dependence of overlay field cracking performance on overlay thickness and fracture energy of asphalt mixture. A total of 15 pavement sections in Minnesota for which Disk-shape Compact Tension (DCT) testing was performed on field cores from overlays were used for the study. Due to the difference in the overlay lives, different cracking performance measures such as average transverse cracking rate (ATCR), maximum transverse cracking rate (MTCR) and transverse cracking performance index (TCTotal) were calculated. These cracking performance measures were compared with asphalt overlay thicknesses and DCT fracture energies. The analysis indicated the dependence of TCTotal on both overlay thickness and fracture energy. The observed relationship was assessed for reliability using a statistical analysis and a new performance parameter that combines overlay thickness with fracture energy is proposed to provide measure of total fracture resistance of the overlay. Preliminary thresholds are also proposed for selection of overlay thicknesses and material types in new overlays. [ABSTRACT FROM AUTHOR]

Abstract Regular maintenance is paramount for a healthy road network, the arteries of any economy. As the resources for maintenance are limited, optimization is necessary. A number of conflicting objectives exist with many influencing variables. Although many methods have been proposed, the related research is very active, due to difficulties in adoption to the actual practice owing to reasons such high-dimensional problems even for small road networks. Literature survey tells that particle swarms have not been exploited much, mainly due to unavailability of many techniques in this domain for multi-objective discrete problems like this. In this work, a novel particle swarm algorithm is proposed for a general, discrete, multi-objective problem. In contrast to the standard particle swarm, the bare-bones technique has a clear advantage in that it is a parameter-free technique, hence the end users need not be optimization experts. However, the existing barebones algorithm is available only for continuous domains, sans any particle velocity terms. For discrete domains, the proposed method introduces a parameter-free velocity term to the standard bare-bones algorithm. Based on the peak velocities observed by the different dimensions of a particle, its new position is calculated. A number of benchmark test functions are also solved. The results show that the proposed algorithm is highly competitive and able to obtain much better spread of solutions compared to three other existing PSO and genetic algorithms. The method is benchmarked against a number of other algorithms on an actual pavement maintenance problem. When compared against another particle swarm algorithm, it not only shows better performance, but also significant reduction in run-time compared to other POS algorithm. Hence, for large road network maintenance, the proposed method shows a lot of promise in terms of analysis time, while improving on the quality of solutions. [ABSTRACT FROM AUTHOR]

This work shows the self-healing results of surface cracks on bituminous mixtures after microwave heating. Different mixtures (semi-dense AC, BBTM and PA) with diverse types, sizes and proportions of metallic additions were tested (steel wool, steel filing and metallic powder). 3 aspects were evaluated: a) influence of the mass and type of addition on the heating speed; b) temperature increase ratio with the specific energy; c) monitoring of the healing process using ultrasounds. It was found that metallic filler replacing the mineral powder was the most efficient and practical addition. This method allows complete closure of the cracks, using an industrial waste, and offers certain improvements compared to induction heating. The results validate the microwaves healing capacity, as well as the use of ultrasounds for tracking the crack depth. [ABSTRACT FROM AUTHOR]

Sustainable highway pavement maintenance is important for achieving sustainability in the transportation sector. Because the three aspects included in sustainability metrics (environment, economy, and society) often contradict each other, maximising the sustainability performance of highway pavements is difficult, especially at the network level. This study developed a novel multi-objective heuristic algorithm to formulate sustainable highway pavement network maintenance plans considering carbon emissions (CE), life cycle agency cost (LCAC), and pavement long-term performance (LTP). The proposed algorithm is a new variant of multi-objective differential evolution (MODE) that incorporates self-adaptive parameter control and hybrid mutation strategies embedded in its framework (MOSHDE). Three state-of-the-art multi-objective heuristics, namely, the non-dominated sorting genetic algorithm II(NSGA-II), classic MODE, and multi-objective particle swarm optimisation (MOPSO), as well as the proposed MOSHDE, were applied to an existing highway pavement network in China for performance evaluation. Compared with other heuristic algorithms, the proposed self-adaptive parameter control strategy enables the automatic adjustment of the control parameters, avoiding the time-consuming process of selecting them and enhancing the robustness and applicability of differential evolution. The hybrid mutation strategy uses both exploration and exploitation operators for the mutation operations, thus leveraging both global and local searches. The results of the numerical experiment demonstrate that MOSHDE outperforms the other tested heuristics in terms of efficiency and quality and diversity of the obtained approximate Pareto set. The optimal solutions obtained by the proposed method correspond to a proactive maintenance policy, as opposed to the reactive maintenance policy commonly adopted in current practice. In addition, these solutions are more cost-effective and environmentally friendly and can provide better pavement performance to highway users over the project life cycle. Therefore, the proposed MOSHDE may help practitioners in the transportation sector make their highway infrastructure more sustainable. [ABSTRACT FROM AUTHOR]

• Rubber modified 3DPA has good viscosity, elasticity, compatibility, high temperature and printability with 80 mesh and 18% of crumb rubber, and 4% of C 9 petroleum resin; • Only physical blending is occurred and C 9 petroleum resin play an effective compatibilization role in R−3DPA; • Recommended printing temperature and the speed of R−3DPA is 150 ∼ 160 °C and 1 cm/s. The application of 3D asphalt printing technology can be used to effectively improve the automation level and reduce the construction risk in pavement maintenance. In order to prepare and optimize 3D printed asphalt with good high-temperature performance and printability by sustainable utilization of waste rubber powder, the conventional properties and printability of rubber modified 3D printed asphalt (R-3DPA) were analyzed according to the basic properties and printing tests. The results were used to determine the optimal mesh and content of crumb rubber and additive content of C 9 petroleum resin. Then, the thermal storability and high temperature rheological property of R-3DPA were studied by phase separation test and dynamic shear rheological test. Fourier transform infrared spectroscopy and fluorescence microscopy were used to analyze the modification mechanism of R-3DPA. The printing temperature and speed were determined by a 3D printing test. The results show that R-3DPA has good viscosity, elasticity, compatibility, high-temperature rutting resistance, and printability with 80 mesh and 18 % of crumb rubber and 4 % of C 9 petroleum resin. Physical blending occurred, and C 9 petroleum resin can play an effective compatibilization role in R-3DPA. The recommended printing temperature and speed R-3DPA are 150–160 °C and 1 cm/s. [ABSTRACT FROM AUTHOR]

Abstracts Environmental sustainability in transportation infrastructures can be achieved by using recycled materials. Commonly, road and airport pavement construction is identified as a greatly polluting factor for greenhouse gas and odor emissions. This paper presents a case study concerning two rehabilitation methods adopted in a reconstruction project of two taxiway pavements in a major Italian airport. The paper describes the entire process of rehabilitation works starting from the preliminary investigations to the final quality controls. It includes the pavements design phase and the materials optimization and environmental assessment, which is the core of the research. The findings show that recycling does not necessarily result in lower performance. In fact, up to 65% of CO 2 e emissions were saved by constructing the recycled pavements. Performance was instead comparable to a standard asphalt pavement. Finally, the paper shows the eco-efficiency of including low-energy treatments and sustainable strategies into pavement construction to enhance environmental savings and cost effectiveness in airport construction practices. [ABSTRACT FROM AUTHOR]

Public projects for pavement and pavement maintenance are often based on budgets set by capital improvement budgets. A better way for determining the cost of sustainability in infrastructure costs is needed. The capitol budget limitation causes an issue for the owner. The municipality must construct projects with a focus solely on initial cost and cannot include sustainability requirements due to the perceived additional cost. Sustainability can often be viewed as subjective. Utilizing the carbon footprint as the basis for the decision creates a much more objective evaluation of sustainability in pavements. A case study illustrating a carbon footprint cost index is presented. [ABSTRACT FROM AUTHOR]

Road network expansion in Egypt is considered as a vital issue for the development of the country. This is done while upgrading current road networks to increase the safety and efficiency. A pavement management system (PMS) is a set of tools or methods that assist decision makers in finding optimum strategies for providing and maintaining pavements in a serviceable condition over a given period of time. A multi-objective optimization problem for pavement maintenance and rehabilitation strategies on network level is discussed in this paper. A two-objective optimization model considers minimum action costs and maximum condition for used road network. In the proposed approach, Markov-chain models are used for predicting the performance of road pavement and to calculate the expected decline at different periods of time. A genetic-algorithm-based procedure is developed for solving the multi-objective optimization problem. The model searched for the optimum maintenance actions at adequate time to be implemented on an appropriate pavement. Based on the computing results, the Pareto optimal solutions of the two-objective optimization functions are obtained. From the optimal solutions represented by cost and condition, a decision maker can easily obtain the information of the maintenance and rehabilitation planning with minimum action costs and maximum condition. The developed model has been implemented on a network of roads and showed its ability to derive the optimal solution. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an analytical approach for joint planning of pavement maintenance and resurfacing activities that minimizes pavement lifecycle costs, including user, maintenance and resurfacing costs, for an infinite time horizon. The optimization problem is formulated as a nonlinear mathematical program with continuous pavement state and continuous time, and optimality conditions are derived. Managerial insights and practical implications are drawn from two realistic application scenarios, where the maintenance cost is either independent of or linearly dependent on pavement condition, to address impacts of routine maintenance activities on pavement resurfacing planning decisions. Numerical examples demonstrate clear trade-offs between maintenance and resurfacing activities in terms of both pavement improvement effectiveness and costs. This paper shows that maintenance activities, if applied optimally, have the potential to significantly prolong pavement service life between consecutive rehabilitations and reduce overall pavement lifecycle costs. [Copyright &y& Elsevier]

Abstract: With regard to limits in budget, inevitably, one must choose prioritized projects in pavements rehabilitation and maintenance process. This paper looks into prioritization based upon a model including all effects of important factors like pavement condition index, traffic volume, road width as well as rehabilitation and maintenance cost. Since defining a model that introduces all those factors was difficult, a more advanced modeling named fuzzy logic was referred for the problem of prioritization. Although analytical hierarchy process can be used for decision making process as well, fuzzy modeling lets one have more precise choices for the outcome. Finally with the help of MATLAB software and coded M-files, inference engines such as Product engine, Dienes–Rescher and Lukasiewicz were all tested and the logical favorite separation for this application was found in product inference engine. As a case study some streets located in district No. 6 of Tehran municipality were selected and the favorite mathematical model was executed on those streets. This model was used for prioritizing these 131 sections. [Copyright &y& Elsevier]

Abstract: Accurate predictions of future pavement conditions are essential for determining the most cost-effective maintenance strategy. The current methods for assessing pavement conditions involve either equipment measures or visual inspections. Equipment measures are not extensively implemented because of high cost; thus, subjective evaluations by road inspectors are often used as a replacement. Nevertheless, visual inspections could draw in errors and variations due to subjectivity and uncertainty. The present serviceability index (PSI), one of the most common indicators used to evaluate pavement performance, is incapable of transforming one’s imprecise judgment into an exact number between 0 (the worst) and 5 (the best). Conventional regression cannot deal with visual inspection data that are linguistic or non-crisp. In contrast, fuzzy regression is capable of handling such fuzzy data. In this paper, pavement conditions are exemplified by five membership functions and estimated by using fuzzy regression to better account the uncertainties of the traditional method. Also, a similarity indicator is applied to measure the goodness of fit. A case study using pavement inspection data is presented to establish estimated fuzzy regression equations. The results demonstrate the capability of the model, which is able to assist road administration units to determine desirable repair actions regarding the predicted pavement conditions. [Copyright &y& Elsevier]

Abstract: Roadside slope failures often result in day to week-long traffic disruption and are a major problem in Nepal so that timely maintenance of roadside slopes needs greater priority for smooth operation of traffic. In this paper, we develop a Geographic Information Systems (GIS)-based maintenance model considering pavement and roadside slope stability conditions. A pavement maintenance priority map is prepared based on pavement condition. International Roughness Index (IRI) is used as the pavement condition index. Similarly, a roadside slope maintenance priority map is produced by analyzing slope stability condition. An integrated maintenance priority map is produced by combining both pavement and roadside slope maintenance priority maps with consideration of weighting of each maintenance component. The integrated maintenance priority index developed in the research lies from 1 to 3, and is distributed heterogeneously. Higher index values qualify for higher priority in maintenance planning. Thus, a conventional method of maintenance planning under the constraints of budget, time and resources can be improved by incorporating the actual condition of pavement and roadside slope failure susceptibility, which has the potential to improve significantly the serviceability of the road system. The study shows that GIS, which can manage and visualize different types of data together or separately, can help the decision making process for road maintenance planning in the Himalayan regions. [Copyright &y& Elsevier]

During the pavement life cycle, construction and rehabilitation activities and vehicle-road interactions provoke extensive environmental, economic, and social impacts. Therefore, decision-making systems are developed to derive optimal construction and rehabilitation plans, alleviate the environmental and economic burdens, and simultaneously increase the social benefits. The past studies have developed management systems with different management approaches, optimization tools, objectives, constraints, prediction models, performance indicators, evaluation techniques, evaluation boundaries, and risk paradigms. This study presents and discusses their diverse perceptions and methodologies for these management system elements. Besides the drawbacks in the adopted perceptions, the study presents the further investigations required to develop more efficient systems that optimally achieve the environmental, economic, and social objectives. The review is limited to studies of the international journals undertaken in the past 20 years, which conferred the project-level management of construction and rehabilitation of flexible pavements. [Display omitted] • Impact of Management system on construction and rehabilitation plans. • Roles of management system objectives, constraints, models, and indicators. • Decision variables of construction and rehabiliatation plans. • Cost subsets and environmental burdens factors fostered in the management system. • Constituting risk assessment in decision-making process. [ABSTRACT FROM AUTHOR]

• An overview of pothole formation, classification and maintenance was reported. • A comprehensive comparison between different kinds of patching materials was made. • Repair methods, cost and durability of cold mix patching materials were studied. • Cold patching materials components and their impact on the patch were inspected. • Methods of evaluating cold mix patching materials performance were investigated. Cold Mix Patching Materials (CMPMs) are usually used instead of Hot Mix Asphalt (HMA) to repair potholes and localized distresses. Although these materials provide immediate serviceability, they have a relatively short life. However, worldwide interest in these solutions, which started as fragmented industrial initiatives, is growing. This article provides a critical comparison between several aspects regarding using CMPMs and HMA in repairing potholes. Specifically, repair techniques, productivity and costs were investigated in detail. Plus, the impact of the main crucial factors, i.e., workability, bonding, water susceptibility, stability, and storageability, on the performance of CMPMs was investigated through an overview. [ABSTRACT FROM AUTHOR]

The single life cycle assessment on advanced vehicle technologies and clean construction supply chains offers the potential for reducing carbon dioxide emissions from vehicle operation and road infrastructure separately. However, the impact of the combination of these two aspects on CO 2 emissions mitigation of road life cycle is less known even though it is critical to the longer-term road transportation decarbonization and long-range policy making for transportation sector, especially under latest worldwide net-zero carbon emission goal. In this study, taking a real project-level asphalt pavement freeway with 15-year life span in China as a case, the amount and hot spots of CO 2 emissions of road transportation were evaluated by considering emissions abatement measures of advanced vehicle technologies and construction supply chains which are theoretically practicable in near-, mid-term and long-term future (from 2020 to 2035). Furthermore, a scenario-based sensitivity analysis on different increasing scope together with various increasing degree of abatement levels over time for these measures is provided. Results demonstrate that the timely implementation of combined decarbonation measures of advanced vehicle technologies and construction supply chains by 2035 could reduce 16.3% of total CO 2 emissions from a road life cycle. In detail, for maintenance activities and use phase, total CO 2 emissions reduce 32% and 16.2% separately. The construction equipment still is the top emissions contributor for maintenance activities. The hybrid electric vehicles (HEV), not battery electric vehicles (EV), replaces conventional internal combustion engine vehicles (ICEV) and becomes the largest source for passenger-related CO 2 emissions from use phase by 2035. Findings are sensitive to assumptions regarding cleaner fuel-produced cement, construction equipment and asphalt, and the market penetration of new energy vehicle. The tight and accelerating pace of primary abatements assist in alleviating the infrastructure carbon lock-in effects caused by maintenance activities with 15% additional CO 2 emissions saving, but not bring about a significant additional reduction (no more than 2.0%) for total road life cycle CO 2 emissions. Current abatement measures are effective but obvious emissions mitigation substitutes of a road is still required, especially innovative road structure and cleaner supply chains inputs as well as deeper decarbonized electrified vehicle. [ABSTRACT FROM AUTHOR]

Pavement maintenance is widely thought to be critical for promoting their sustainability. It plays a pivotal role in sustainable and resilient transportation infrastructure for economic development and social inclusion improvement. Existing research mainly focuses on optimizing the maintenance strategies based on one player but ignores the inherent conflicts and complex interactions among multiplayer decision-makers. To address these issues, this research examined the problem of pavement maintenance involving the highway agency and maintenance service providers under the uncertainty of pavement conditions with the aim of optimizing maintenance strategies. A novel bilevel mathematical model was proposed to handle the inherent conflicts and complex interactions among decision-makers based on the Stackelberg game and Nash game. The goal is to obtain the Stackelberg–Nash equilibrium solution, where the highway agency, as the upper-level leader, determines the maintenance tasks, whereas the service providers, as the lower-level followers, provide the corresponding maintenance activities. To formulate this complex model, a bilevel particle swarm optimization (BLPSO) algorithm was developed for pavement maintenance. Finally, a practical case was used to demonstrate the practicality and efficiency of the proposed model. The results show that the mathematical model can provide feasible and effective pavement maintenance strategies for multiplayer decision-makers in real-world applications. • A bilevel mathematical model is proposed for dynamic long-term pavement maintenance. • Bilevel multiple decision-makers using the Stackelberg–Nash game are incorporated. • A BLPSO algorithm is developed to obtain an equilibrium maintenance strategy. • Comparative results show a significant profit increment for each decision-maker. • The model is feasible and effective for optimizing multiplayer pavement maintenance. [ABSTRACT FROM AUTHOR]

The functional rural road network has a significant effect on the socio-economic growth of a nation. Newly constructed road pavements deteriorate with time, their regular maintenance will not only keep them functional but also increase their service life. Planning and scheduling of maintenance activities is an important part of any maintenance program for a large network of roads. The present study proposes a maintenance plan for low volume rural roads at network level as well as project level. In the first step of network level planning, the roads in the network are prioritized for pavement maintenance, depending primarily on their pavement condition and traffic volume. In the second step of project level planning, a suitable repair and maintenance technique is selected for each road based on the predominant pavement defects, traffic volume, and climatic conditions. ArcGIS was used to visualize the roads on a map and manage the data collected for each road. The maintenance planning was automated through a tool developed within ArcGIS. Verification of the methodology was done by applying it to a case study of 203 rural roads in the state of Himachal Pradesh in India. The results show that the pavement condition of a road (56.4%) is the most critical factor for prioritizing roads for maintenance. Pavement condition is followed by socio-economic facilities located along the road (26.2%), average daily traffic volume (11.7%), and type of connectivity provided by the road (5.7%). The outcome of the maintenance plan proposed in this study is the priority ranking along with the most suitable repair technique for each road in the network. [Display omitted] • A comprehensive pavement maintenance plan is proposed for low volume rural roads in India. • Both spatial and non-spatial information are maintained within a GIS software ArcGIS. • AHP is used as a multi-criteria decision making tool to establish relative importance of each factor. • Most appropriate maintenance technique is selected step-wise based on engineering considerations. • A total of 203 low volume rural roads in the state of Himachal Pradesh in India were included in the case study. [ABSTRACT FROM AUTHOR]

• Database of MSRL test results of large amount of field cores was developed. • GEP model outperformed MLR model with the same database. • Uncertainty analysis was conducted through the Monte Carlo simulation. • Binder property dominates rutting resistance of in-service middle asphalt layer. For a multilayered asphalt pavement, rutting resistance of the mixture in the middle asphalt layer underneath the surface course plays a significant role in the high-tempearture stability of the whole pavement structure. Thus, evaluation of the rutting resistance of the middle asphalt layer using field cores is often necessary for project-level pavement maintenance decision-making. However, the extrusion and tests of field cores are time-consuming and destructive to pavement. To address this problem, developing an empirical model to predict the rutting resistance of the middle asphalt layer at a certain service time from historical test results may be a potential alternative. This study aims to address this challenge by using the gene expression programming (GEP) method and a database composed of a large number of multiple-stress repeated load (MSRL) test results of field cores. By correlating the compound creep rate (CCR) of the middle asphalt layer from the MSRL tests to material properties, environmental and traffic parameters, field rutting depth, and middle layer age, the optimal GEP model was developed, and then compared with the conventional multiple linear regression (MLR) model built on the same database. Uncertainty analysis was also conducted through the Monte Carlo simulation (MCs). It was found that the GEP model outperformed the MLR model, with a 6%-7% higher R-square. The uncertainty analysis allows the transport agencies to estimate the reliability of their prediction and make maintenance and rehabilitation (M&R) plans according to the specified reliability target. [ABSTRACT FROM AUTHOR]

• Parameters, RRDD and IAR, are proposed to evaluate the treatment effectiveness. • Multiple regression analysis is employed to investigate the effect of initial RD and AADT on effectiveness. • LCCA is performed to evaluate the treatment cost-effectiveness over a 50-year analysis period. • HIR outperforms other treatments in restoring pavement rutting resistance. • Establishment of the rutting-based maintenance decision-making system is recommended. 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. [ABSTRACT FROM AUTHOR]

With growing maintenance demands whereas limited budgets, an integrated methodology unifying life-cycle assessment (LCA), life cycle cost assessment (LCCA) and multi-objective optimization is proposed to establish maintenance decision-making system, considering performance, economic as well as environmental dimensions. Firstly, system scope and unit process of the methodology are redefined considering pavement industry in China. Next, assessment models and parameters are determined to establish the inventory. Then, LCCA is adopted to convert environmental footprint into an economically measurable unit - environmental damage cost (EDC). Lastly, a programming optimization is executed to obtain the optimal maintenance schedule over the whole pavement life cycle. To verify, a case study based on an existing highway in southeast China is conducted, considering ECA-10 thin overly (ECA-10), milling and resurfacing the upper layer (MRU) and hot-in-place rehabilitation (HR) strategies. Results indicate that user cost is the dominant factor whereas environmental impact is relatively negligible. Pavement design life and service life of maintenance alternatives have significant influence on the optimal schedule, and longer pavement design life should be considered when conducting LCA-based programming optimization. With the extension of design life, MRU shows the best long-term benefit. Materials and construction are the main stages potentially improved. Few attempts have been made to introduce LCA into the pavement industry of China, but this model successfully contributes to sustainability goal and scientific decision-making. [ABSTRACT FROM AUTHOR]

• 8 highway segments, in total 491.74 km, were investigated in field. • Treatment effectiveness was quantitatively compared by PJ, DRR and ADRR with RD. • Rutting tests by cylindrical samples was proposed and successfully performed. • Applicability of proposed effectiveness analyses was assessed by rutting tests. • High-quality RAP are recommended for timely maintenance activities. To evaluate the effectiveness of maintenance treatments for asphalt pavement, four types of treatments, including the hot in-place recycling (HIR), milling and resurfacing (M&F), thin HMA overlay (THO) and microsurfacing (MS), were analyzed. 8 highway segments, in total 491.74 km, in Jiangsu Province in China, were investigated and the data of rutting depth (RD) in their maintenance history was collected. Based on the data of RD, the effectiveness of four treatments was quantitatively compared by three indicators, namely, performance jump (PJ), deterioration rate reduction (DRR) and average deterioration reduction rate (ADRR). Moreover, the applicability of the proposed effectiveness analyses was assessed by laboratory rutting tests with field cylindrical samples. Results indicate that the HIR is the most effective treatment, followed by M&F and THO. While the MS is the least effective treatment, whose service life is only three or four years. The findings highlight the significance of the proper traffic opening time after maintenance to avoid the weakened rutting resistance caused by high-temperature mixtures, the effect of the RD before maintenance on maintenance decision-making, and the application of high-quality RAP in the timely maintenance activities. Therefore, the performance-based maintenance strategy should be establish to improve pavement performance and extend pavement service life. Further research on the pavement performance after RAP application is necessary. [ABSTRACT FROM AUTHOR]