EVALUATION OF HIGHWAY MATERIALS AND DESIGN PERFORMANCE

Description

ABSTRACT

This report reviews new and improved highway construction materials and technologies, identifying materials that can improve highway performance, replace scarce or unavailable natural materials, and contribute to more sustainable high- ways. The materials and processes identified have all either been introduced within the past 5 years and are not yet widely used or are still in development. They included advances in cements, concretes, asphalt binders, asphalts, metallics and polymers, aggregates, and other materials. Also included are materials that reduce noise, improve smoothness, allow for faster placement and shorter construction times, reduce energy consumption, capture CO2, and lower costs. For each material, the report provides a description, applications, benefits, costs, current status, and sources of additional information.

CHAPTER ONE

1.0                                                      INTRODUCTION

This report presents a review of the availability of advanced construction materials that show promise for routine highway construction and rehabilitation on the Federal Highway System. The Federal Highway System includes over 200,000 mi (321,868 km) of interstate and primary highway system in all 36 States of Nigeria. The highway design on this system consist of asphalt pavements (also referred to as asphalt concrete [AC] or flexible pavement) and concrete pavements (also referred to as portland cement concrete [PCC] or rigid pavements). The pavement type denotes the material used for the surface layer, the wearing course of the pavement. Each pavement type is built up of layers, starting with the existing subgrade with each successive layer utilizing better quality material.
The most costly layers and the layers that are designed and constructed to be the most durable layers are the surface layers—consisting of AC or PCC.
One lane-mile of PCC pavement can require about 4,800 T (4,354 t) of concrete for a surface layer that is 12 in. (300 mm) thick. Also, 1 lane-mile of continuously reinforced concrete pavement (CRCP) can require about 100 to 120 T (91 to 109 t) of steel. In U.S. northern and coastal areas, the steel in CRCPs and the steel used at joints in jointed concrete pavement need to be protected to minimize the potential for corrosion that can lead to early failures of CRCPs and jointed pavements.
As indicated, every year large amounts of aggregate materials and manufactured materials are needed to support highway construction and rehabilitation in Nigeria. However, the poor availability of good-quality aggregates in many parts of the country and the increasing financial and societal costs to produce the needed manufactured materials are creating a concern for planners and engineers. It is, therefore, important that new and improved sources of highway construction materials be developed that will result in improved performance of the highway system, be cost-effective, and incorporate sustainable technologies. Sustainability consideration in highway construction and rehabilitation is of recent origin. However, its impact on the well-being of the Nation’s highway infrastructure cannot be underestimated, as discussed next.

1.1                                                     AIM OF THE STUDY
The aim of this work is to analyze and interpret field and laboratory test results to identify and address issues with materials for employees of State, local and Federal agencies involved in highway construction. However, industry and academia will also be considered.

1.2                                               OBJECTIVE OF THE STUDY
Upon completion of the study, the student will be able to:

• Select the most appropriate materials for highway construction based on material characteristics, engineering properties, design requirements, cost, availability, and expected service life.
• Utilize quality assurance principles in order to make effective material acceptance decisions that conform to accepted plans and specifications.
• Analyze and interpret field and laboratory test results to identify and address issues with materials.
• Evaluate the technical aspects of the specifications to determine whether best practices in the selection, placement, sampling, testing, and inspection of materials are being specified.
• Identify promising new technologies, best practices for implementation, and methods for promoting the transfer of knowledge associated with the selection, placement, sampling, testing, and inspection of innovative materials.
• Evaluate innovative materials and products and select information about the innovation that is required for specification development.

1.3                                                   SCOPE OF THE STUDY
In many parts of Nigeria, supply of acceptable quality aggregates is very limited. In addition, the production of portland cement is very energy intensive and also accounts for high carbon dioxide (CO2) emissions. Expectations for the future are that restrictions will be placed on cement production and the cost of cement production will rise to meet environmental regulations. Similarly, the availability of asphaltic binders is dependent on the supply of oil and oil industry efforts to maximize use of oil refining by-products. As a result, it is expected that the cost of asphalt binders of highway pavement grade will remain high, and the supply is expected to be inadequate to meet Nigeria demand.
Cost of construction materials continues to increase every year. In addition, use of marginal materials results in early development of pavement distress, requiring more frequent repairs and rehabilitation and associated lane closures and traffic congestion in high-volume traffic areas.
Traffic congestion also increases the potential for construction-zone accidents and increased levels of environmental pollution related to automobile emissions. Therefore, there is a strong desire in Nigeria to optimize the use of materials currently used for highway pavement construction and to seek advanced materials that are cheaper, better performing, and less damaging to the environment.

1.5 NEEDS FOR ADVANCED HIGH-PERFORMANCE MATERIALS ON HIGHWAY DESIGN

The needs for seeking advanced highway construction materials include:

• Reduced costs—get more lane-miles constructed or rehabilitated for a given constrained budget.
• Conservation of resources—support national efforts to create sustainable solutions to minimize impact of construction on the environment.
• Reduced ecological footprint.
• Extended service life.
• Optimized use of locally available materials.
• Achieving environmental benefits—reduced carbon footprint, reduced congestion-related emissions.
• Reduced work zone–related traffic delays and safety concerns—use materials that reduce the potential for early failures.