Existing Pavement Condition Research Articles

A Genetic Algorithm-based Decision Framework to Incorporate Climate Impact on Pavement Maintenance Planning

A recent trend of increase in the vulnerable behavior of roads to potential climate events is observed worldwide. However, a few studies conducted incorporate climate impact into road maintenance and rehabilitation. To address this, a genetic algorithm (GA) based optimization approach is proposed in this study with a climate risk index (CRI) in terms of criticality of roads, probability of occurrence of a climate event, and existing severity level of pavement. Criticality is defined by road functional class, availability of alternative routes and land use. Probability is determined by historical events and topography, while severity is defined by existing pavement condition. The CRI is incorporated as a generic constraint to the GA-based optimization model to maximize the average network condition under a given budget. To demonstrate this, a case study is conducted using twenty roads in different climatic conditions in Sri Lanka. The results show that in 25% and 50% of required total budget conditions there is a clear separation between priority roads IRI and non-priority roads IRI due to the generic constraint. This is an indication that the optimization model effectively prioritizes roads when there is a budget constraint. This concludes that the proposed approach can be utilized to make the most of the available budget for road maintenance by prioritizing roads that are highly vulnerable to climate events without compromising the overall network condition. Further, the proposed maintenance optimization approach can be extended to long term maintenance planning economically for developing countries.

Effect of existing pavement condition and overlaying strategy on the reflective cracking resistance of asphalt pavement

Overlaying becomes more and more popular as a method to improve the driving quality and structural integrity of the pavement. The existing pavement condition needs to be evaluated when selecting the proper overlaying strategy. In this paper, the existing pavement condition of four field pavement projects was surveyed and the crack amount and crack pattern were monitored before asphalt overlaying and 1–2 years after the overlaying paving. It was found that thermal crack was initiated within two pavement projects, whereas the reflective crack was observed within other pavement projects with transverse cracks in the existing pavement. The potential factor that could induce the above field crack pattern difference was identified. Additionally, the Finite Element Method (FEM) analysis was conducted to study the effects of existing pavement conditions on crack propagation and the crack resistance of a new overlaying strategy. Results show that the J-integral of crack tip is increased and then decreased with the increase of crack length. The higher modulus of the existing layer leads to a larger value of J-integral while the aging effect of overlay contributes to delay crack propagation of the existing layer. The crack width of the existing layer has less effect on the J-integral at the crack tip of overlay. In addition, a new overlaying strategy is proposed to alleviate the reflective crack, in which multi-layer overlays are constructed and the geogrid is employed and placed between the existing pavement layer and the bottom layer of overlay, as well as other interfaces between any two adjacent overlays. Such a strategy is found to be effective in reducing reflective cracks by using simulative modeling.

International Roughness Index prediction for flexible pavements using novel machine learning techniques

International Roughness Index (IRI) is an important pavement performance indicator that is widely used to reflect existing pavement condition and ride quality. Due to the importance of this significant index, the current research aims to develop a precise IRI prediction model using the Gaussian Process Regression (GPR) and Locally Weighted Polynomials (LWP). The long-term pavement performance (LTPP) datasets of pavement age, initial IRI, alligator, longitudinal and transverse cracks, standard deviation of rutting, and subgrade plasticity index variables are employed in predicting IRI. These datasets are collected from 126 different flexible pavement sections of the LTPP specific pavement studies (SPS-1) located in different climatic zones in the US. The total number of IRI measurements in the collected database is 925 which covers a wide range of IRI values. Multiple linear regression (MLR) is firstly applied to classify the input variables. Then the MLR model is compared with four machine learning techniques which are GPR, LWP, Particle Swarm Optimization-Adaptive Network based Fuzzy Inference System (PSO-ANFIS) and PSO-Artificial Neural Networks (PSO-ANN). The developed models’ performance is validated using different statistical indices, including the coefficient of determination (R2). The results demonstrate that the GPR (R2=0.93) and LWP (R2=0.90) outperformed the PSO-ANFIS (R2=0.65) and PSO-ANN (R2=0.52) in predicting IRI. Thus, the GPR model is found to be more accurate for IRI modeling compared to the hybrid investigated models.

Airfield Asphalt Overlay Design for Non-conventional Pavement Structures: A Case Study of Airport in Indonesia

Airfield pavements begin a gradual deterioration from several sources, including traffic load and environmental conditions. To achieve its intended design life, routine maintenance, repair, and rehabilitation should be performed. There are considerable research and studies conducted on the design and practice of pavements rehabilitation/overlay for typical airfield pavements. However, most of the existing guidelines and studies are only suitable for pavements with conventional structures. There has been no detailed investigation into the practice of airfield asphalt overlay for non-conventional pavement structures, such as chicken claw /Cakar Ayam pavement system and nailed-slab system. In the present article, challenges and issues for airfield asphalt overlay design for non-conventional pavement structures were examined based on an actual runway rehabilitation project in one of the major airports in Indonesia in 2015. The overlay design procedure, the evaluation of the existing pavement condition, including visual surveys and deflection tests, and the pre-overlay treatments were also discussed. In addition, a finite element (FE) simulation to model the non-conventional pavement structure was developed to calculate the required overlay thickness. The result showed that, during the overlay design of non-conventional pavement structure, data from falling weight deflectometer (FWD) could not be directly used to estimate the back-calculated layers moduli because of the difference in the geometric features of the pavement structure. Moreover, the FE model can be a robust tool to simulate the complex three-dimensional geometric features of a non-conventional pavement and important loading conditions, such as interface shear bond of overlay, that are usually not available in other tools, such as FAARFIELD. Finally, this study showed that the additional asphalt overlay could reduce the fatigue stress at the bottom of the existing slab and vertical stress at the top of the subgrade, resulting in overall smaller stress levels

Performance-based design of asphalt pavements concerning the reliability analysis

Fatigue is one of the most common types of distress in asphalt pavement due to traffic loading. Pavements are steadily deteriorating from a long-term issue of cracking resulting in reduced durability and increased maintenance cost. While limit states design methods have been adopted to enhance the service life of pavements, literature demands development in performance-based design models for these infrastructures. Hence, this study proposed a new performance-based design procedure for fatigue characterization of asphalt pavements at various performance levels. To do so, a performance-based limit state function was utilized to measure the reliability level of the pavements concerning accumulative fatigue failure. Then, the severity levels of the loading scenarios were defined based on the statistical analysis of the random variable WIM (weigh-in-motion) data and the pavement resistance formulated using the rational performance levels. Accordingly, the structural reliability analysis was conducted to determine the reliability level of the existing pavement condition. Eventually, the observed reliability indices were recommended to assure the reliability concern under the given performance level subjected to considered loading scenarios.

Modeling the Effects of Asphalt Overlay Design on Pavement Distress Initiation with Random Parameters Hazard-Based Duration Models

Pavement deterioration model is a key input to a pavement management system that optimizes pavement maintenance and rehabilitation (M&R) planning. As a typical pavement M&R technique, asphalt overlay is commonly implemented to restore pavement performance. However, the impact of its design factors on pavement deterioration is not well documented in existing publications. This study aimed to investigate the effects of asphalt overlay design on the initiation of various types of cracking and severe rutting with consideration of endogenous bias and unobserved heterogeneity. A series of random parameters Weibull duration models were developed based on 317 asphalt overlay projects, which were collected from the Long-Term Pavement Performance program. Endogenous overlay design, overlay thickness, milling indicator, and overlaid pavement deflection were identified to represent their heterogeneity caused by unobserved factors over highway sections. Based on analysis results, the endogenous overlay design was shown to underestimate the service life of overlaid pavement. The occurrence probability of overlaid pavement distress would significantly decrease with an increase of asphalt overlay thickness. The application of 30% reclaimed asphalt pavement materials would retard the occurrence of severe rutting, but accelerate the occurrence of all types of cracking. Relative to asphalt overlay, milling and overlay can significantly reduce the hazard rate of severe rutting and all types of cracking. In addition, existing pavement condition, overlaid pavement deflection, traffic volume, and climate factors were identified to have significant effects on the distress initiation in overlaid pavements.

Comparative study on structural evaluation of flexible pavement using BBD and FWD

Flexible pavements undergo deterioration with increase in heavy traffic. Thus, there is a need to evaluate the existing pavement condition and undertake appropriate maintenance measure for safe and efficient flow of traffic. Benkelman Beam Deflectometer (BBD) and Falling Weight Deflectometer (FWD) are the most widely used non-destructive techniques for evaluation and strengthening of flexible pavements in India. There is a need for rational approach of pavement evaluation because of high cost associated with new road construction and limited financial resources for maintenance of roads. Benkelman beam deflectometer involves static loading whereas falling weight deflectometer involves dynamic loading which simulates moving traffic. The main objective of this study is to develop a correlation between FWD and BBD. This paper presents a typical case study on a 5 km length of National Highway from chainage 34+006 to 39+003 in Bangalore, Karnataka. Pavement structural evaluation is conducted using FWD and BBD. The tests were conducted on the same road stretch at the same point of loading. The results are analyzed as per Indian Road Congress (IRC) guidelines and overlay thickness is designed using KGP-BACK and IIT-PAVE. Linear correlation between BBD and FWD is developed using central deflection values and the co-efficient of correlation (R2) is found to be 0.8994. The developed correlation is then validated for present study data and available literature data. The root mean square error is found to be 6.77 and 7.67 respectively. Based on the observations, it is concluded that FWD serves as one of the more reliable method for the structural evaluation of pavements and this method proves to be cost effective by reducing the desired overlay thickness.

Appraising Pavement Surface Distresses And Expected Mitigation Measure On Selected Road Segment

The work visually inspects and evaluate the pavement failures and their causes as well as resolution methods. It is quite important to examine and identify the causes of the failed pavement to select a proper treatment option. The study consisted of two tasks: the first covers the detail visual inspection of the existing pavement failures, whereas the second investigates the actual causes of these failures. From Areka to Wolaita Sodo was selected for investigation. An intensive field work was carried out on the existing pavement condition of this road. It was found that most of the damaged pavement sections suffered from severe cracking, potholes and raveling failures. These failures might have been caused by fatigue failures on pavement structure due to the movement of heavily loaded truck – trailers. The damage could also be attributed to poor drainage, inadequate design and improper pavement materials.

Multi-objective optimization of pavement preservation strategy considering agency cost and environmental impact

Road network requires timely maintenance to keep pavement surface in good condition for reduction of fuel consumption with the limited budget. This study focused on development of pavement preservation strategies in the road network considering multi-objective optimization of agency cost and environmental impact (in terms of CO2 emission). Field data from long-term pavment performance (LTPP) database were used to quantify the impact of pavement preservation treatments (crack seal, chip seal, and thin overlay) on the changes of surface roughness. The emission rate functions of vehicles with respect to speed and pavement surface condition were developed using Motor Vehicle Emission Simulator (MOVES) with the updated tire rolling resistance coefficients. The multi-objective optimization problem was solved using the Simulated Constraint Boundary Model (SCBM) method. The final solution was recommended based on the minimized distance from the utopia point to the Pareto front. The results show that the optimization solutions are affected by the available budget, existing pavement condition, truck traffic, and unacceptable level of pavement roughness. For multi-objective optimization of minimizing both agency cost and CO2 emission, the recommended preservation treatments among different segments is a combination of crack seal and thin overlay in most cases. These findings can be used by highway agencies to make road maintenance decisions considering the tradeoff between agency cost and environmental impact.

An optimization model for synchronous road geometric and pavement enhancements

Abstract A synchronous optimization model for rehabilitation of existing two-way two-lane (TWTL) highways is proposed in this paper considering geometric modification and existing pavement rehabilitation. The rehabilitation process of existing roadways is categorized into geometric design modifications and pavement repairs. These two types of modification apply separately in roadway life-cycle because of the difference in nature of these repairs, which impose an extra cost and time of closure to road users and owners. This paper aims to address the modification of existing highways by a new approach linking the existing pavement condition and geometric configuration changes of the developed roadway to provide the optimum vertical alignment. The proposed procedure depends on various parameters of existing pavement condition, cross-section configuration, traffic volume and composition, and current alignment composure. In the first step, all these dependencies are explained and quantified with separate cost models. For each solution, the overall cost is calculated with a life-cycle cost analysis approach. Finally, a particle swarm optimization (PSO) based model is developed to find the optimum solution. The developed model was applied in two case studies with good and adverse geometric conditions. The results show that there is a critical condition in the roadway segments which have all these conditions: (1) the grade is more than three percent, (2) the grade is following with reverse grade, and (3) decommissioning of the asphalt concrete (or extended to lower layers) exist. The optimum solution in these critical conditions suggests the modification of the geometric configuration before the pavement rehabilitation in order to reduce the overall cost. In the absence of these conditions, the optimum alignment is more analogous with the existing alignment of the highway.

Cracking models for HMA overlay treatment of composite pavements in Louisiana

ABSTRACT Cracking is one of the primary forms of distress suffered by hot-mix asphalt (HMA) overlay of composite pavements. Pavement cracking affects the ride quality and pavement service life by allowing water and debris to penetrate through the pavement structure. This paper presents the development of transverse cracking and longitudinal cracking performance models for overlay treatment of composite pavements in the state of Louisiana. Various factors that affect the cracking performance of overlay treatment were identified. Such factors include equivalent single axle load (ESAL), thickness of HMA and Portland cement concrete (PCC), functional classification of roadways, and newly developed temperature indexes. Regression analyses were performed to identify those factors and to develop cracking prediction models. In order to better predict the pavement service life, the existing condition of the pavement was also utilised through the models. The developed models provided an acceptable agreement between the measured and predicted crack values. It was found that the predictions were improved when the existing pavement condition was incorporated in the models. The resulting cracking models could be used by Louisiana Department of Transportation and Development (LADOTD) as a good pavement management tool for timely pavement maintenance and rehabilitation actions to maximise benefits, driver’s comfort, and safety.

Sustainable Highway Maintenance: Optimization of Existing Highway Vertical Alignment Considering Pavement Condition

Any change in the geometric configuration of the existing road affects other dependent elements such as travel time, fuel consumption, and existing pavement. This paper quantifies these effects and finds an optimum geometric configuration. Three separate models are developed in this research: (1) the travel time model which predicts vehicles flow speed on the specified geometric condition, traffic composure, and evaluates the imposed costs to the road users; (2) the fuel consumption model, which estimates needed propulsive force and anticipated fuel for vehicles passing through the road; and (3) the pavement rehabilitation cost model considering two main constraints of existing pavement condition and project line elevation. The developed pavement rehabilitation model proposes the best solution for pavement rehabilitation practice and computes associated costs. Particle Swarm Optimization (PSO) is used to find the optimum solution in a minimization problem search space. The proposed model is applied to a real-world case study. Results show that there is an extremely less tendency for change, even with the existence of adverse geometric conditions, when there is a relatively good pavement condition. In the case of deteriorated pavement conditions, economic justification for geometric modification is required.

Evaluation of the Impact of Existing Condition and Overlay Characteristics on Asphalt Overlay Design and Performance based on a Mechanistic-Empirical Approach

The present study sought to determine how the overlay design and performance of asphalt concrete (AC) were affected by existing pavement condition and overlay material properties. To that end, this study was performed in different scenarios of traffic and structure with the latest AASHTO design software AASHTOWare (version 2.3). The modulus and rut depth of existing layers, the interface condition between AC overlay and existing pavement, and the AC overlay properties of Poisson’s ratio and performance grade were addressed in the current study. Besides the overlay thickness design, the investigation also focused on pavement performance to determine how separate distresses were impacted by existing pavement condition and the properties of the overlay material. The investigation produced three major outcomes, as follows: the current AC layer thickness and design traffic determined the extent to which the existing AC layer condition affected the overlay design thickness; the overlay performance and design were not significantly affected by the existing base and subgrade condition; and fatigue cracking was more strongly influenced by the existing AC layer modulus and interface bonding condition compared with the rutting potential.

Effects of existing concrete pavement condition on performance of unbonded jointed plain concrete overlay

Abstract Unbonded concrete overlay (UBCO) is the most used pavement rehabilitation technique across United States with an overall usage of 47% amongst all the rehabilitation methods. It is aimed to improve the performance of any deteriorated/cracked jointed plain concrete pavement (JPCP). Unbonded JPCP overlay involves placement of a separation layer of hot mix asphalt (HMA), which acts as a stress relief layer between the existing concrete pavement and the overlay. There are numerous factors that affect the design and performance of UBCOs and out of these, existing pavement condition or the severity of damage of existing pavement is a prime factor. The severity of damage is described by the distressed elastic modulus thus, accurate determination of the distressed elastic modulus of the existing concrete pavement is essential for predicting the accurate performance of the unbonded overlay. This study focuses on analyzing the impact of distressed modulus by conducting simulations in the AASHTOWare pavement ME design software version 2.3 and evaluating the predicted performance of JPCP overlay for two different climatic regions. The results indicated that the distressed modulus of existing concrete pavement affects the performance of the overlay with regards to transverse cracking, joint faulting and pavement roughness. Transverse cracking is the most affected performance parameter with a change of 0.27%–2.31% with a unit change in distressed modulus. The impact of climatic conditions on the performance of unbonded overlay was also observed. The adverse effects of distressed modulus can be minimized by reducing the joint spacing or increasing the overlay slab thickness.

PERFORMANCE EVALUATION OF COLD RECYCLING EXPERIMENTAL STRETCH CONSTRUCTED WITH RBI-GRADE-81 AT BANGALORE UNIVERSITY

The bituminous pavement rehabilitation alternatives are mainly overlaying, recycling and reconstruction. In the recycling process the material from deteriorated pavement, known as reclaimed asphalt pavement (RAP), is partially or fully reused and it is a valuable approach for technical, economical, and environmental reasons. Full Depth Reclamation (FDR) is one of the cold methods of recycling the bituminous pavements. In this study an experimental stretch is selected for FDR in which the full flexible pavement section and a predetermined portion of the underlying materials are milled and remixed with about 10 % of 10 mm down size aggregate and 30 % stone dust to match the Bituminous Concrete (BC) Grade-I mix limits and known quantity of RBI 81 stabilizer. Stabilization of RAP material with RBI grade 81 reduces the requirement of new materials, time of construction and increases the strength of the road. This report consist of a case study of road constructed at Jnanabharathi campus, Banglore University, which include assessment of existing pavement condition and the preparation of pavement surface for the construction of stabilized layer and construction aspects of pavement using RAP material stabilized with RBI grade 81. The report also presents results of some short term functional and structural condition studies on the study stretch. From the limited studies carried out it is concluded the RAP material can be used effectively by the stabilization with RBI grade 81. From the field studies it is concluded that the strength of the pavement increases with increase in RBI grade 81 dosages.

Evaluation of pavement surface friction subject to various pavement preservation treatments

This study compared the effectiveness of preservation treatments on pavement surface friction and investigated the long-term variation of friction using the data collected in the Specific Pavement Studies-3 (SPS-3) of the Long Term Pavement Performance (LTPP) program. The SPS-3 focuses on the effect of four preservation treatments (thin overlay, chip seal, crack seal, and slurry seal) on pavement performance under five design factors (traffic, precipitation, temperature, existing pavement condition, and subgrade type). Both the simple ranking method and statistical methods (boxplot and Fisher’s Least Significance Difference test) were used to compare the effectiveness of preservation treatments on friction improvement. The statistical analysis results indicate that slurry seal causes significantly greater friction number compared to the control section; and the ranking from high to low based on the average friction number among four preservation treatments is: slurry seal, chip seal, thin overlay and crack seal. Among the five design factors, subgrade type and existing pavement condition show less influence on pavement friction compared to climate and traffic factors. Stepwise regression analysis was conducted to quantify the influence of various factors (material, traffic, temperature, precipitation, and freezing index) on the long-term variation of pavement friction within the monitoring period. It was found that the application rate of slurry seal and chip seal affected the friction variation and temperature showed negative correlation with friction. In addition, pavement roughness was found having certain correlation with friction for the control sections and the sections with crack seal.

Use of Structural Condition Index for Pavement Structural Evaluation Tool

Abstract In this study, an effort was made to evaluate pavement condition using the pavement structural condition index (SCI), which isbased on falling weigh deflectometer (FWD) deflection basin and structural numbers that incorporated various levels of traffic andsubgrade resilient modulus. Extensive field validations were conducted to assess the effectiveness of SCI along with comparisonof pavement distress and condition score restored in the Pavement Management Information System (PMIS). The analysis resultsrevealed that the SCI appears to realistically capture the existing pavement condition compared to the pavement scores and fieldsurvey results. Based on this finding, probabilistic and deterministic models were developed to estimate SCI when FWD data isnot available. These models are deemed most useful for network-level analysis purposes to aid establish pavement maintenanceand rehabilitation plans.Key words: Falling weigh deflectometer deflection basin, Pavement structural condition index, Pavement management informationsystem, Probabilistic and deterministic models, Subgrade resilient modulus

Rutting Model for HMA Overlay Treatment of Composite Pavements

Timely rehabilitation and preservation of pavement systems are imperative to maximize benefits in terms of driver’s comfort and safety. However, the effectiveness of any treatment largely depends on the time of treatment and triggers governed by treatment performance models. This paper presents the development of rutting model for overlay treatment of composite pavement in the State of Louisiana. Various factors affecting the rutting of overlay treatment were identified. Regression analysis was conducted, and rut prediction model is generated. In order to better predict the pavement service life, the existing condition of the pavement was also utilized through the model. The developed models provided a good agreement between the measured and predicted rut values. It was found that the predictions were significantly improved, when existing pavement condition was incorporated. The resulting rutting model could be used as a good pavement management tool for timely pavement maintenance and rehabilitation actions to maximize LADOTD benefits and driver’s comfort and safety.

Field Evaluation of Surface Friction Performance of Chip Seals in Indiana

Chip seal has been widely used as an effective surface treatment for pavement preservation. The Indiana Department of Transportation (DOT) chip sealed a total of 373 lane mile pavements in 2008 and 700 lane mile pavements in 2009. However, many issues, such as the optimal use of local materials and new aggregates, remained unsolved. No original information was available at the time for Indiana DOT engineers to assess the performance of chip seal pavements. A research study was initiated by the Indiana DOT to evaluate the field performance of chip seal pavements, particularly the surface friction properties. Eighteen chip seal projects were selected as the test sections for this study. Field testing was conducted to measure pavement surface friction and texture properties. The true surface friction numbers were identified for chip seals after 12 months of service. The variation of surface friction on chip seals was analyzed. Factors affecting chip seal surface friction, such as aggregate, traffic volume, and existing pavement condition, were identified and examined. Three traffic levels were defined for better chip seal application. The international roughness index on the existing pavement affected chip seal friction performance. A criterion was recommended for assessing the friction performance of chip seal and identifying the possible failure of a chip seal.

Impacts of ethanol plants on highway networks

This paper describes the impacts of the ethanol industry on existing highway infrastructure in the vicinity of an ethanol production plant. To determine the impacts of plant location, the corn and soybean draw areas are estimated on the basis of crop prices. Crop production data are extracted from satellite imagery of the crop data layer produced by National Agricultural Statistics Service and the United States Department of Agriculture. The increase in truck traffic attributable to the ethanol plant is estimated for the changed flow of feedstock. A model is run for two scenarios: existing corn and soybean production; and increased corn and soybean production. Based on existing pavement condition and incremental traffic changes, the funds required to maintain the affected roads at their present service levels are quantified.