A. Veeraragavan

Application of Highway Development and Management Tool for Low-Volume Roads

Connectivity is a key component of rural development in developing countries. Traditionally, many road organizations budget and program for road works on a historical basis. An objective, needs-based approach is necessary with knowledge of the content, structure, and condition of the roads being managed. The Highway Development and Management Tool (HDM-4) provides a suitable framework for such an approach. From the available traffic and condition surveys, nine representative low-volume road sections with varying geometry and pavement condition are analyzed. The types of vehicles using the roads are two- and three-wheelers; standard medium buses; standard minibuses; light commercial vehicles; two-axle trucks, cars, and tractors among the motorized traffic; and bullock cart and bicycle among the nonmotorized traffic, which are the conventional modes of transport for low-volume roads in developing countries. The purpose of the study is to forecast budget requirements and predict performance trends by applying the strategy analysis of HDM-4 to low-volume roads. The analysis was carried out for two objective functions: to maximize the net present value and to minimize the total costs for a target international roughness index. The design period was 20 years; economic indicators were determined at a discount rate of 12%. Two investment alternatives, namely, a desired maintenance and an ideal maintenance, are compared with the do-minimum alternative. The study reveals that the strategy application of HDM-4 can be used for managing low-volume roads effectively. The tool will help in forecasting budget requirements and assessing the impact of various investment alternatives.

Pavement Life–Extending Potential of Geosynthetic-Reinforced Chip Seal with High-Reflectivity Aggregates

High temperatures in asphalt pavements lead to rutting and age-related cracking. Although beneficial for reducing distresses, thicker layers are not generally used in low-volume roads because of cost restrictions. This paper presents an alternative approach in which a geosynthetic-reinforced chip seal layer with high-reflectivity aggregates is used to reduce the temperature in asphalt pavements and therefore reduce the potential of rutting and the rate of aging. If the absorption of the surface of the pavement is lowered and the conductivity of the layers is reduced, then less heat will penetrate through the depth of the pavement, and a lower pavement temperature will result. The absorption at the surface can be reduced through the use of a surface layer with greater reflectivity, and the conductivity can be reduced with the help of a layer of a material that has very low conductivity. Therefore, a composite pavement system can be used for low-volume, asphalt-surfaced roads; the system would incorporate an insulation layer and a high-reflectivity surface layer. The insulating layer will also effectively protect the surface from air and therefore significantly reduce the oxidation exposure and aging of the asphalt binder and the resultant stiffening of the asphalt mix. Analyses of modeling or simulation data and field data from a test section demonstrated a significant reduction in temperature throughout the depth of a pavement and an extension of life by three to four times.

Combined Model Framework for Asphalt Pavement Condition Determination After Flooding

Flooding of pavements often causes damage that is invisible on the surface. A way to predict the condition of a pavement after flooding will be useful for agencies to make rational decisions about the need for closing a road to traffic or opening it up for cleaning and recovery work. In this study, the problem of flooded pavement assessment was formulated as a combination of hydraulic and structural analyses. A model was developed; it consisted of results from unsaturated hydraulic and layered elastic structural analyses. An interactive simulation was developed from the model and was made available on the web to users in the public domain. Simulations with the model showed significant impacts when subgrade layer moduli were below 50 MPa and layer thickness was less than 200 mm for the hot-mix asphalt (HMA) and less than 600 mm for the base. Axle loads exceeding 80 kN exacerbated damages and hazardous conditions. The time to reach conditions that will not lead to damage or failure within a short period of time depends on both the pavement conditions and the load magnitude. On the basis of thickness of surface HMA layer and soil subgrade moduli, restrictions of traffic could be placed on flooded pavements.

Sensitivity of Design Parameters on Optimal Pavement Maintenance Decisions at the Project Level

Sensitivity analyses are important parts of both studying complex systems and measuring the variation in input parameters on the response. They are useful to decision makers for understanding the robustness of the optimal solution that they are to adapt to variations of the parameters of the problem. The sensitivity of the optimal solution of a project-level pavement management problem is analyzed, and the robustness of the optimal solution to the interventions and the timing, cost, and benefit are investigated. The input parameters, which affect the optimal maintenance solution, are identified as the structural and functional condition parameters (defined in terms of deflection and roughness, respectively, at the beginning of the analysis period), traffic volume, growth rate, and discount rate. The problem of computing the optimal treatment and timing for a given budget level is modeled as a mixed integer nonlinear optimization problem and solved by using a computationally efficient network-optimization technique. The benefits are evaluated by considering the pavement performance and are quantified as the area between the performance curve and the threshold values. The optimal budget required for pavements in different structural and functional conditions as well as traffic levels is presented. The effect of initial pavement condition on the optimal maintenance actions as well as their timings is studied. The result of the sensitivity analysis showed that the cumulative standard axle loads and traffic growth rate have a significant effect on the selection and timing of rehabilitation and preventive maintenance actions. The effect of the discount rate on the maintenance management decisions is also presented.

Prioritization of Low-Volume Pavement Sections for Maintenance by Using Fuzzy Logic

A pavement management system formulated according to the specific needs and resources of a highway agency should ensure satisfactory pavement performance with minimal maintenance cost. The success of a pavement management system depends on the pavement condition data, accuracy of the prediction of pavement performance, and project-and network-level rehabilitation planning. Of these, the most labor-intensive, time-consuming, and costly component is the collection of pavement condition data. The inventory data include roughness, skid resistance, and surface distresses. Although mechanical instruments are available for rapid collection of roughness and skid resistance data, the collection of distress data for low-volume rural roads is still manual and hence labor-intensive and time-consuming. Subjective rating techniques prove to be a solution to this problem, but their reliability is poor due to the subjectivity associated with them. Therefore, there is a need for a rapid and cost-effective yet reliable method for collecting pavement condition data. The Prime Ministers Gram Sadak Yojana is a project launched in India by the Government of India to provide all-weather road connectivity to rural habitations. The investment is around 600 billion rupees (

Cluster-Based Pavement Deterioration Models for Low-Volume Rural Roads

15 billion) during the period 2000–2007. As part of the project, road stretches are prioritized for maintenance and reconstruction by using the pavement condition index. The quantification of the severity and extent of data collected is affected by each panel members perception and judgment. To deal effectively with the subjectivity associated with human judgment of distress severity and extent, mathematical techniques of fuzzy set were used. Fuzzy membership functions were formulated for severity, extent, and relative importance of each distress with respect to maintenance. Fuzzy condition indices were used to prioritize the pavement sections by suitable fuzzy ranking methods. The effectiveness of the method is established by ranking pavement sections.

Application of Highway Development and Management Tool in Rural Road Asset Management

The management of low-volume rural roads in developing countries presents a range of challenges to road designers and managers. Rural roads comprise over 85 percent of the road network in India. The present study aims at development of deterioration models for the optimum maintenance management of the rural roads under a rural road programme namely Pradhan Mantri Gram Sadak Yojana (PMGSY) in India. Visual condition survey along the selected low-volume rural roads considers parameters like condition of shoulders, drainage features, cross-drainage structures, and camber, and pavement distresses, namely, potholes, crack area, and edge break, are collected for a period of three years. The deterioration models have a significant role in the pavement maintenance management system. However, the performance of a pavement depends on several factors. Cluster analysis can be used to group the pavement sections so that the performance of pavements in different clusters can be studied. Nonhierarchical clustering technique of k-means clustering was considered. Separate deterioration models have been developed for each of the clusters. A comparison of the models developed with and without clustered sections reveals that the clustering of pavement sections are preferred for the efficient rural road maintenance management.

Laboratory and Field Investigation of Mechanistic Properties of Foamed Asphalt Recycled Base Course Materials for High Volume Pavements in India

Road asset management is a systematic process of maintaining, upgrading, and operating road assets cost-effectively. Several thousand kilometers of rural roads have been constructed during the past few years in India. The performance of these newly constructed roads under actual traffic, climate, and environmental conditions will be monitored periodically; and a database with data on their performance will be created. The database can be used in planning and scheduling of maintenance activities to preserve the rural road infrastructure by use of sound engineering principles. This paper is an attempt to highlight the various issues that need special attention to preserve the rural road infrastructure assets that are created in the country. The paper presents the effect of timing of maintenance on the pavement condition during the design life and the increased agency cost due to the delay in maintenance intervention. The application of computer-based pavement management tools such as the Highway Development and Management Tool in planning and scheduling of appropriate maintenance strategies is highlighted.

Decision Support Models for Asset Management of Low-Volume Roads

The quality of cold in-place recycling (CIR) is strongly dependent on the capability of proper laboratory investigation and design, and quality control during construction. The objective of this study was to evaluate the quality of the first major foamed asphalt CIR recycled layer in India, laid on a national highway in India. A nonnuclear density gauge (NNDG) and a portable seismic properties analyzer (PSPA) were utilized to determine the density and stiffness of the foamed asphalt recycled layer. In addition, cores and material samples from the recycled layer were also tested in the laboratory for density and stiffness using dynamic modulus tests and the seismic method. The results of tests were related to material properties and critical factors influencing the performance-related properties were identified. Comparisons between laboratory and field sample data were made. Foaming temperature and gradation control of crusher dust were identified as parameters requiring tight control to achieve the required quality. The detrimental effects of excess blending of cement were also revealed. The NNDG and the PSPA were found to be capable of identifying poor quality areas both in midsections and at joints, and to be capable of monitoring the quality of recycled layer.

Application of Factor Analysis in Maintenance Management of Low Volume Roads

Pavement maintenance decisions are based on skimpy rules and rules of thumb. Generally, the selection of roads for maintenance is based on a worst-first policy. The timing of maintenance intervention and standards adopted for maintenance govern the service life of the pavement. The rate of pavement deterioration depends on the timing of maintenance intervention, choice of the type of maintenance treatment, and the quality of the construction. In the present investigation, the periodic performance data of typical low-volume rural roads constructed under the rural road development programs in India are considered. Performance prediction models are developed. The models are used to predict the performance during the design life. Different maintenance interventions are considered at different pavement conditions. The effect of the timing of maintenance on agency costs and vehicle operation costs is quantified and presented.