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Rigid and Flexible Pavements
| http://www.enggpedia.com/civil-engineering-encyclopedia/dictionary/highway-a-transportation/1564-flexible-and-rigid-pavement |
Development of a country depends on the connectivity of various places with adequate road network. Roads are the major channel of transportation for carrying goods and passengers. They play a significant role in improving the socio-economic standards of a region. Roads constitute the most important mode of communication in areas where railways have not developed much and form the basic infrastructure for the development and economic growth of the country. The benefits from the investment in road sector are indirect, long-term and not immediately visible. Roads are important assets for any nation. In the past, gravel road surfaces, cobblestone and granite setts were extensively used, but these surfaces have mostly been replaced by asphalt or concrete.
There are various types of pavements depending upon the materials used. Basically, all hard surfaced pavement types can be categorized into two groups, flexible and rigid. Flexible pavements are those which are surfaced with asphalt materials. These types of pavements are called “flexible” since the total pavement structure “bends” due to traffic loads. A flexible pavement structure is generally composed of several layers of materials which can accommodate this “flexing”. On the other hand rigid pavements are composed of a PCC (Portland Cement Concrete) surface course. Such pavements are “stiffer” than flexible pavements due to the high modulus of elasticity of the PCC material.
State highway agencies generally select pavement type either by policy, economics or both. Flexible pavements generally require some sort of maintenance or rehabilitation every 10 to 15 years. Rigid pavements, on the other hand, can often serve 20 to 40 years with little or no maintenance. Thus, it should come as no surprise that rigid pavements are often used in urban, high traffic areas. But, when a flexible pavement requires major rehabilitation, the options are generally less expensive than for rigid pavements.
Date: 2015-12-12; view: 543; Нарушение авторских прав; Помощь в написании работы --> СЮДА... |