Using the Long Term Pavement Performance Database in Pavement Design Courses

The Strategic Highway Research Program Long Term Pavement Performance (LTPP) database provides considerable information about a large number of pavement test sections. The information may be easily accessed using DataPave 2.0 software, available free from the Federal Highway Administration. This software provides information on approximately 3,000 sections, with several modules for data analysis and extraction. This paper describes the integration of LTPP DataPave 2.0 software into a pavement design course. The database was used at several points throughout the course, including lessons on traffic characterization, materials, reliability, performance, and design. Twelve Texas pavement case studies were used. Each student was required to complete an individual project requiring the use of the database. Student projects and student evaluations of the use of the DataPave 2.0 software in this course are also discussed. This paper provides sufficient information for interested faculty to implement the use of DataPave 2.0 in their own courses in pavement design and related areas.     

Risk-Based Model for Valuation of Performance-Specified Pavement Maintenance Contracts

Many transportation agencies have started outsourcing maintenance activities to contractors by means of performance-based contracts. These outsourcing contracts are intended to transfer performance-based risk from transportation agencies to private contractors for a premium cost. Even though such contracts provide numerous benefits to both contractual parties, there are equally many concerns with their implementation. Certainly, one of the most important concerns is how to quantify performance-based risk. This paper presents a general and flexible framework for quantifying the performance-based risk in terms of premium cost for different contract specifications and preventive maintenance and rehabilitation strategies. The framework developed consists of three modular components: (1) the reliability-based pavement performance model; (2) the preventive maintenance and rehabilitation models; and (3) the pricing model. The developed framework is illustrated using the current design and rehabilitation methods for flexible pavements.     

Computer Simulation Model: Construction Analysis for Pavement Rehabilitation Strategies

Most state highways in the United States were built during the 1960s and 1970s with an infrastructure investment of more than $1 trillion. They now exceed their 20?year design lives and are seriously deteriorated. The consequences are high maintenance and road user costs because of degraded road surfaces and construction work zone delays. Efficient planning of highway rehabilitation closures is critical. This paper presents a simulation model, Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS), which estimates the maximum amount of highway rehabilitation/reconstruction during various closure timeframes. The model balances project constraints such as scheduling interfaces, pavement materials and design, contractor logistics and resources, and traffic operations. It has been successfully used on several urban freeway rehabilitation projects with high traffic volume, including projects on I-10 and I-710. The CA4PRS helps agencies and contractors plan highway rehabilitation strategies by taking into account long-life pavement performance, construction productivity, traffic delay, and total cost.     

Critical Analysis of Different Hilbert-Huang Algorithms for Pavement Profile Evaluation

Pavement profile analysis is a major component in pavement infrastructure management decision making for maintenance and rehabilitation. This paper takes an in-depth look at pavement profile characterization and evaluation, taking into account the inherent nature of road profile data, i.e., nonstationary and non-Gaussian. Although there have been several studies aimed at the analysis and characterization of pavement profile, the bulk have been limited to applying relatively conventional signal processing techniques, such as the Fourier analysis. Using this approach, only the average condition of the local conditions can be represented. Most transient and changing signals will not be handled well due to the averaging effect of the technique. The Hilbert-Huang transform operates at the scale of every oscillation, an extremely important property for obtaining localized profile information. In this paper, the different algorithms of the Hilbert-Huang transform: empirical mode decomposition (EMD), ensemble EMD, and complex EMD (CEMD) have been discussed and implemented to extract useful information from road profile data. The robustness of the algorithms is compared based on its ability to produce physically meaningful intrinsic mode functions (IMFs) which truly characterize the underlying process. The results show that although all the methodologies yielded similar residual trends, the CEMD produced physically meaningful and trusted IMFs whose information at the various levels of decomposition could be used to extract profile information such as the extent of deterioration and localized roughness information.     

玻璃纤维土工格栅在沥青路面改造中的应用

分析了沥青混凝土路面裂缝成因及玻璃纤维土工格栅的性能，在旧沥青路面与补强层之间铺设一层玻璃纤维土工格栅。能有效防治或减缓原沥青路面的反射裂缝，延长道路的使用寿命。     

Gray System Model for Estimating the Pavement International Roughness Index

The international roughness index (IRI) is a measurement of pavement roughness that is widely accepted for evaluating pavement serviceability, especially its riding quality. Generally, as the age of pavement increases, its condition deteriorates and its IRI value increases. However, the IRI data collected from the Indiana highway system indicate that the IRI values vary considerably for similar pavements and traffic conditions at any given pavement age. This makes it difficult to establish the relationship between IRI and pavement age. In this study, the gray system theory was used to estimate the maximum, mean, and minimum IRI values at different pavement ages. It is believed that the three IRI values are essential for evaluating pavement serviceability. This paper presents the process of the gray system modeling for IRI estimation and discusses the effects of traffic volume on pavement roughness and the estimation accuracy of the gray system models.     

Case Study of Urban Concrete Pavement Reconstruction on Interstate 10

Many urban concrete pavements in California need to be reconstructed, as they have exceeded their design lives and require frequent maintenance and repair. Information is needed to determine which methodologies for pavement design, materials selection, traffic management, and reconstruction strategies are most suitable to achieve the objectives of California Department of Transportation’s (Caltrans) long-life pavement rehabilitation strategies (LLPRS) program. To develop construction productivity information for several construction windows, a case study was performed on a Caltrans concrete rehabilitation demonstration project near Los Angeles on Interstate-10, where 20 lane-km was successfully rebuilt using fast setting hydraulic cement concrete (FSHCC) with one weekend closure for 2.8 lane-km and repeated 7- and 10-h nighttime closures for the remaining distance. The concrete delivery and discharge controlled the overall progress. In terms of the number of slabs replaced per hour, the 55-h weekend closure was 54% faster than the average nighttime closure. An excellent traffic management strategy helped to reduce the volume of traffic during the weekend closure and minimize the traffic delay through the construction zone.     

Dynamic Numerical Analysis of Antimoisture-Damage Mechanism of Permeable Pavement Base

As a permeable base material of pavement, the large stone porous asphalt mixture (LSPM) is used widely in China to lessen the moisture damage of the asphalt pavement. However, the dynamics mechanism of the inhibitory effect of permeable base on moisture damage is not clear yet. The dynamic fluid-solid coupling analysis of the saturated pavement with LSPM base course, considering the asphalt mixtures as the porous medium, was performed using the finite difference numerical code FLAC3D. Numerical results revealed that the positive and negative dynamic pore pressure alternated in the pavement with the approaching and leaving of the wheel loads. The phenomenon of water pumping out of and sucking into the pavement under the moving loads was proved. The flow of fluid in pavement can be regarded as the laminar flow. The presence of the LSPM base course greatly decreased the dynamic pore pressure and the scouring force in the surface course because of the large permeability coefficient of the LSPM. The location of the maximum dynamic pore pressure also changed due to the LSPM base course. Due to the permeable base, the dissipation of the dynamic pore pressure was accelerated and thus the moisture damage was lessened.     

Global Optimization of Pavement Structural Parameters during Back-Calculation Using Hybrid Shuffled Complex Evolution Algorithm

In this paper, the use of a hybrid evolutionary optimization algorithm is proposed for global optimization of pavement structural parameters through inverse modeling. Shuffled complex evolution (SCE) is a population-based stochastic optimization technique combining the competitive complex evolution with the controlled random search, the implicit clustering, and the complex shuffling. Back-calculation of pavement layer moduli is an ill-posed inverse engineering problem, which involves searching for the optimal combination of pavement layer stiffness solutions in an unsmooth, multimodal, complex search space. SCE is especially considered a robust and efficient approach for global optimization of multimodal functions. A desirable characteristic of the SCE algorithm is that it uses information about the nature of the response surface, extracted using the deterministic Simplex geometric shape, to direct the search into regions with higher posterior probability. The hybrid back-calculation system described in this paper combines the robustness of the SCE in global optimization with the computational efficiency of neural networks and advanced pavement system characterization offered by employing finite-element models. This is the first time the SCE approach is applied to real-time nondestructive evaluation of pavement systems required in the routine maintenance and rehabilitation activities for sustainable transportation infrastructure.     

A Simplified Model for Pavement Drainage

In this paper, we present a simplified model for pavement drainage system. The model accounts for the accumulation and flow of water through a drainable base and edge drain representing a porous medium. There is an inflow through a portion of the boundary (pavement surface) as well as an outflow through a separate part of the boundary (outlet pipe). The model consists of an initial value problem governing the growth of the region saturated with water and an elliptic boundary value problem describing the flow of water within that region. The model is validated using rainfall and outflow data obtained from an instrumented site. The proposed model can be used to evaluate the characteristics of a pavement drainage system as well as to estimate its permeability.     

Data Integration of Pavement Markings: A Case in Transportation Asset Management

Effective transportation asset management requires the implementation of tools such as software, hardware, databases, and data collection systems. Pavement markings make up one component in transportation asset management, which are complex networks that require large databases. Typically these databases are maintained in different areas within an agency and are most often incompatible. Combining new and old tools, this paper addresses the need for better data integration and utilization while incorporating current information technologies. Specifically, this paper presents integrated transportation asset management system for estimating the current and future condition of pavement markings. The paper describes the data structure, in the form of a physical model, integrating a pavement marking relational data schema with existing information technology systems. Software was found to be useful in developing the data schema. The software produced an extensible markup language file that is compatible with a variety of existing database structures such as Oracle, SQL, and MS Access. Additionally, the system included an algorithm, which implements the data structure and predictive models to estimate the condition of the asset at any point in time or space on the highway system. Using either measured data or predicted data the system gives managers an opportunity to decide on the best possible condition state of the asset and perform queries or optimizations. Ultimately, managers can develop cost effective strategies for pavement marking asset management.     

Multimodal Approach to Seismic Pavement Testing

A multimodal approach to nondestructive seismic pavement testing is described. The presented approach is based on multichannel analysis of all types of seismic waves propagating along the surface of the pavement. The multichannel data acquisition method is replaced by multichannel simulation with one receiver. This method uses only one accelerometer-receiver and a light hammer-source, to generate a synthetic receiver array. This data acquisition technique is made possible through careful triggering of the source and results in such simplification of the technique that it is made generally available. Multiple dispersion curves are automatically and objectively extracted using the multichannel analysis of surface waves processing scheme, which is described. Resulting dispersion curves in the high frequency range match with theoretical Lamb waves in a free plate. At lower frequencies there are several branches of dispersion curves corresponding to the lower layers of different stiffness in the pavement system. The observed behavior of multimodal dispersion curves is in agreement with theory, which has been validated through both numerical modeling and the transfer matrix method, by solving for complex wave numbers.     

DCP Criteria for Performance Evaluation of Pavement Layers

The potential use of the dynamic cone penetrometer (DCP) for evaluation of the pavement distress state is investigated. A model to predict the distress level of pavement layers using penetration rate (PR) values of the subgrade and aggregate base course (ABC) layers is proposed based on the coupled contribution of the subgrade and the ABC materials. The developed distress model is validated using field data from four test sites. The two sites with good condition rating values (equal to 4 and 3) are found to have an unconfined PR-ABC value <4 mm∕blow, a PR-subgrade value <25 mm∕blow, and an ABC layer thickness that exceeds 152 mm (6 in.). A discrepancy that seems to appear in the field data (a high field California bearing ratio value corresponding to a PR-ABC value >4 mm∕blow) is explained by the fact that field-measured California bearing ratio values for the ABC layer are affected by the strength of the underlying subgrade soils. This is especially observed in cases where the thickness of the ABC layer is <102 mm (4 in.). The framework of the established procedure can generally be used at other sites, properly taking into account differences in material properties.     

Cost-Effectiveness Evaluation of Warranty Pavement Projects

Warranty contracts are expected to enhance product quality and service life at lower life-cycle cost. Recognizing that such benefits could be offset by the generally higher costs of warranties, an assessment of the relative cost-effectiveness of warranty contracts compared to their traditional counterparts is currently of great interest. Using pavement data from Indiana, this paper evaluates the costs, effectiveness, and cost-effectiveness of warranty and traditional contracts. Effectiveness was measured in terms of pavement condition and treatment service life. The paper determined that the warranty contracts generally had higher agency costs but produced pavements with superior condition and service life, and lower construction periods and work-zone user costs, compared to their traditional counterparts. Over a 5-year period, the warranty contracts were found to be 27–30% less cost-effective than their traditional counterparts. Over the long term, the warranty contracts were found to be 70–90% more cost-effective on the basis of service life and 58–65% more cost-effective on the basis of both service life and pavement condition. The study results suggest that the higher long-term cost-effectiveness of warranty contracts is more perceptible when both cost and effectiveness are viewed over the entire life of the pavement treatment and when both agency and user cost are used in the cost analysis. The paper discusses certain aspects of such comparative evaluation studies that could lead to biased inferences and calls for careful screening of warranty and traditional contracts for such studies.     

Analysis of Nighttime Driver Behavior and Pavement Marking Effects Using Fuzzy Inference System

Nighttime driving behavior differs from that during the day because of differences in the driver’s field of view. At night, drivers must rely on their vehicle headlamps to illuminate the roadway. It is essential then that the roadway delineation system provide the appropriate lane guidance to motorists when navigating a roadway, particularly one that is curvilinear. A nighttime driving experiment was conducted to collect user perception data of various pavement markings and markers applied to horizontal curves. The effectiveness of each pavement marking was rated using a subjective scale. A fuzzy inference system was used to analyze the subjective pavement marking and marker evaluation ratings provided by the research participants. Pavement marking effectiveness, horizontal curve sharpness, and driver age were used to develop a fuzzy index for nighttime driving condition (FIND). Based on the FIND, the results indicate that drivers prefer that a combination of treatments be applied to horizontal curves rather than only a single treatment. A bright centerline, bright edgeline, and bright retroreflective raised pavement maker combination treatment, and a bright centerline and bright edgeline combination treatment, resulted in the highest FIND score. A bright, 8-in. (20.3 cm) edgeline, applied alone to a horizontal curve, scored the lowest FIND.     

PCC Airfield Pavement Response during Thaw-Weakening Periods

A field study was performed at two regional airports in Wisconsin during spring thaw to determine its effects on portland cement concrete (PCC) airport pavements. This study was part of a research program to model the performance of airfield pavements for the Federal Aviation Administration. Subsurface temperature and falling weight deflection measurements of the pavement structures were taken at both airports and used to calculate the frost penetration depths, the changes in bearing capacity, and the joint and load transfer efficiencies. This paper summarizes the findings of this study and includes several relationships between various engineering properties of the subsurface layers below the PCC layer, along with a procedure for evaluating pavement performance using falling weight deflection data for PCC pavements during spring thaw.     

Normalizing Behavior of Unsaturated Granular Pavement Materials

One of the important components of a flexible pavement structure is granular material layers. Unsaturated granular pavement materials (UGPMs) in these layers influence stresses and strains throughout the pavement structure, and have a large effect on asphalt concrete fatigue and pavement rutting (two of the primary failure mechanisms for flexible pavements). The behavior of UGPMs is dependent on water content, but this effect has been traditionally difficult to quantify using either empirical or mechanistic methods. This paper presents a practical mechanistic framework for determining the behavior of UGPMs within the range of water contents, densities, and stress states likely to be encountered under field conditions. Both soil suction and generated pore pressures are determined and compared to confinement under typical field loading conditions. The framework utilizes a simple soil suction model that has three density-independent parameters, and can be determined using conventional triaxial equipment that is available in many pavement engineering laboratories.     

Stochastic Modeling for Pavement Warranty Cost Estimation

This paper presents a cost estimation model for long-term pavement warranties with multiple distress indicators. One application area for such warranties involves performance-based specifications (PBSs). In contrast to traditional approaches, PBS gives contractors the flexibility to select construction methods, materials, and even design. However, the contractors then must warrant the performance of their work for a specified period of time. Therefore, an accurate estimation of the risks associated with the warranty is a significant cost issue for any contractor to cover potential risks while still being competitive in bidding. Quantitative evaluation of the cost of risk incurred by the warranty has several difficulties. The deterioration of a highway project is a complex process, which is affected by pavement structure, material, traffic load, and weather conditions. Based on a probabilistic risk analysis of failures of performance indicators, the resulting model can estimate the warranty cost at a detailed level. The application of the model has been demonstrated via a numerical case study using long-term pavement performance data.