History of Road Construction and Road Transport & Type of Road Pavement

History

History of Road Construction and Road Transport & Type of Road Pavement

The old roads are un-surface earthen roads or cart-track road eventually the roads were improved with natural soil from ball pits with attention to drainage,

As the traffic increased road were constructed with dry aggregate and sand clays mix in which the former acts as wear resistant and the later as natural binder.

In Water-bound macadam the constituents like rubbles fillers and screener are mix together at site then sprinkle with water and compacted to improve the strength of pavement and to get hard strata.

With a passage of time the density of traffic and traffic load increase the pavements should be designed to withstand and provide quality of riding, proper skid resistance, controlled light reflecting characteristic and a low noise pollution.

Roads are mainly classified into two Types namely Flexible pavement and Rigid pavement.

Flexible Pavement

Flexible Pavement:

It Is a pavement layer comprising of mixture of aggregate and bitumen, heated and mixed properly and then laid and compacted on a bed of granular layer.

Bitumen road has multiple layers:

Prime coat is a coating applied directly to a prepared base course, its act as an initial sealer in the asphalt laying process to block other layer from moisture dust and debris.

Binder course is an intermediate course between the base course and surfacing material consists of aggregate bounded by bituminous material.

Tack coat a very light application of binder to an existing surface to ensure bond between existing surface and new construction. The material is liquid and spread easily.

Surface course is the topmost layer of the road in contact with the traffic, it purpose is to minimize the abrasion of road and reduce adverse effect of climate. Surface course has elastic properties, impervious and takes all wear and tear of the traffic.

Seal coat is the application of top layer with bitumen to seal the voids followed with a cover of stone chips to make the surface watertight.

Rigid Pavement:

Rigid pavement are roads made from concrete, in this type of road the load is distributed by slab action, it assumes that the road is a thick plate and will remain as it is after bending due to load and temperature variation.

The top layers are made up of reinforcement concrete, there is a plain cement concrete layers which acts as leveling course for the RCC layers.

Types of pavements can be adopted depending upon the traffics requirement. To avoid early failure of pavement care should be taken in the design phase.