Friday, 26 August 2016
Pavement Material Characterization and Importance of Using Asphalt Mixture Performance Tester
Importance of highway construction
There are some serious challenges in highway construction that are motivating new approaches to design, build and maintain highways. The construction of highways deals with the planning and designing of service roads for safe, convenient and economical transportation. The main goals of highway construction are to reduce congestion and to improve safety. The environmental effects while developing and maintaining the highway infrastructure is an important concern for the residential public and commuters. Most of the above topics are discussed in the Fundamentals of Engineering exam refresher course material. Therefore, it is important to focus on highway design, construction and safety guidelines for excellent pavement performance.
Primary Pavement Construction Material and its Importance
The present trend of constructing roadway pavements is with cement concrete and asphalt. The pavements provide a convenient riding surface that can be designed to handle heavy loads due to trucking traffic. The pavement construction material plays a predominant role in the durability of pavement surface. Aggregate material used for roadway construction should possess an abrasive resistance property. The requirement of such aggregates is particularly needed when it is to be used in flexible pavements. Asphalt pavements crack due to heavy traffic loads, and the pavement surface experiences wear and tear due to various climatic conditions in addition to heavy traffic loads. The load carrying capacity is mainly based on the base, structural and friction courses of the pavement. Therefore, the aggregates should be hard enough to resist abrasion. Properties of pavement materials is a suggested topic for study prior to the FE exam.
Asphalt Design Mix Variations as per Pavement Design and Standards
The first recorded asphalt road is at 625 B.C., which marks the evidence of asphalt being used in road construction. Today, asphalt paving has become common; ninety percent of all paved roads and streets throughout the nation are paved with asphalt. Asphalt mixes are classified into three types based on the presence of voids in the mix. Each design mix should be designed and recommended for specific use, specific locations and average daily traffic volume, but they also have distinct purposes and advantages. The pavement riding responses are then used as inputs in ride index models. Pavement responses, also known as transfer functions, are used to predict cumulative pavement distresses over a period of time. In the pavement design, it is important to understand the purpose of the pavement. Therefore, we can optimize the selection of materials and mix designs for roadway construction. Once the mix type has been selected, the pavement must be designed accurately to achieve the best performance index. Pavement design considers materials and mixture data for the development of calibration models within the pavement design. Many of the mixtures used today include modified asphalt binders, warm mix asphalt technologies, high reclaimed asphalt pavement contents or recycled asphalt material. Asphalt design structural numbers and pavement layer thickness theory and calculations are discussed in the Transportation Engineering section of the FE exam review course. Asphalt mixture performance tester is an engineering device that is used to test mixtures and their performance for quality control and quality assurance of pavement construction.