The Five Basic Steps of Road Construction

Among the different types of road construction, Earthwork is one of the most crucial. Right-of-way widths can be defined for the entire length of a road. However, special demands are added to the design at intersections. For this reason, planning ahead is necessary to ensure that the road is constructed as smoothly as possible. Listed below are the five basic steps of road construction. Each step has its own importance, and a thorough understanding of each step will ensure that the finished product meets the intended purposes.


The main activity in road construction is earthwork, which entails excavation, transportation, and filling. However, these operations are costly and have large social and environmental consequences. To improve productivity and minimize environmental impact, mathematical models of earthwork are developed. The resulting minimum-cost earthwork plan is derived by a two-phase optimization system. To make use of the mathematical model, the following steps are necessary. After deciding on the objectives of the project, the contractor develops a set of optimization criteria.

The slope of a cut and fill bank is critical during the earthwork operation. A steeper slope requires deeper excavation, increasing construction costs, and increasing slope failure risk. To avoid slope failure, cut and fill banks are constructed at a slope angle that minimizes erosion and slope failure. The slope angle of cut and fill banks varies according to the type of soil and rock available in the area. The slope angle is determined by the slope of the area and the amount of rock available for filling the bank.

Asphalt surfacing

Different sectors require different types of asphalt mixes. The blend should meet specific requirements for various functions and applications. Asphalt must have properties like stiffness, elasticity, and resistance to deformation. In addition, it must be of a suitable workability to allow it to be compacted completely. Typically, hot mixes are used, which are produced at temperatures of up to 190 degrees Celsius. A mix with these characteristics will be more durable than one without these properties.

Many researchers and companies have proposed various alternative surfaces for roads. These alternatives differ in the specific mix composition and durability of the material. A standard asphalt road consists of approximately five per cent bitumen and 95 percent sand, gravel, and stone. Bitumen provides the semi-malleable binder. In the future, a plastic road surface could replace the bitumen. Various factors contribute to the durability of an asphalt surface.


Geo-grids are a kind of geosynthetic material that helps stabilize soil and increase the strength of the surface. They are used during road construction projects as they reduce the tendency of differential settlement and prolong the lifespan of paved roads. Moreover, geo-grids are resistant to a wide variety of environmental factors, including soil microorganisms, UV radiation, and mechanical damage. Moreover, geo-grids can resist high loads and dynamic load for a long period. Additionally, these materials are environmentally friendly, making them a good option for use on roads.

The advantages of using geo-grids in road construction are many. The first one is that it can reduce the risk of rutting and intermixing of soils. Moreover, geo-grids reduce the thickness of unbound base course. By using geo-grids, you can also improve the stability of the surface and minimize the maintenance costs. Geo-grids can also be used in railways and MSE walls.

Flexible pavements

There are several benefits to flexible pavements for road construction. Flexible pavements are pliable and adaptable to environmental conditions. The topmost layer of a flexible pavement must withstand the maximum wear and stress. It is designed to resist imposed loads, avoid water infiltration, and provide a skid-resistant riding surface. Asphalt and concrete are both suitable materials for flexible pavements. Moreover, they have several other advantages.

One of the primary advantages of flexible pavements is that they can flex and reshape under traffic load. This is possible because they have several layers of granular or bituminous materials that are designed to accommodate the flexing. The thickness of the flexible pavement is crucial for limiting the stress on the subgrade, which is usually low in bearing capacity. The quality of the underlying layers of flexible pavement will affect the structural integrity of the pavement.

Subsoil drainage

Subsoil drainage is an important element of road construction and should be considered before and during the project. During the construction process, subsurface drains should be placed in strategic locations to divert water away from potential areas of groundwater. During the design phase, subsurface drains should be located in the base of gullies and beneath sidling fills. Temporary subsoil drains should be discharged through flexible jointed pipes. The drains shall be identified and marked as per As-built plans.

In addition, the frequency of rainfall is a consideration. This factor is based on the life of the road, the amount of traffic and the consequences of substandard drainage. In addition, primary highways commonly incorporate frequency periods of 50 to 100 years. Meanwhile, low-volume forest roads generally incorporate 10 to 25-year frequency periods. The volume of runoff is based on the drainage area, which must be estimated beforehand.

Ground penetrating radar

Ground penetrating radar (GPR) is a cost-effective method for mapping various subsurface objects. It is nondestructive and safe to use in public areas. The technology can provide data of various depths and resolutions, and can be interpreted in real time. Compared to other subsurface scanning methods, GPR is much safer and provides more accurate results. For road construction projects, GPR is especially useful for mapping various structures and utilities, such as bridges and roads.

The accuracy of the system depends on the resolution of the antenna and the sampling rate of the radar signal. Its resolution is 1 cm and the sampling rate is 1024 per scan. The resolution of power diagrams is 1 dB for signal absorption and 4 cm from road level. It is able to scan surface areas of up to one cm2 with a depth of up to 1.5 meters. Moreover, the accuracy is based on the comparison of two conditions: a surface area of one centimeter and a subgrade soil of 1.5 m.

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