Roads are a key part of the infrastructure that is needed for communication between cities and towns and plays a very important part in economic activities. Roads are huge public highways, but can also be private access roads, driveways, and parking lots. Most roads follow the same basic steps in their construction, though there may be differences in the materials, machinery, and technology used on a project.
Road construction has to start with proper planning of the project and making the necessary preparations. The alignment has to be first decided, and for major highways, this can involve detailed surveys that help to decide the alignment and grades. Where land belongs to others, the land has to be acquired and rights of way established, procedures that can often take fair lengths of time. The surveyors have then to mark the entire length of the road with markers that give the construction crews the needed guidance. Contractors then clear all the vegetation on the road alignment and also demolish any obstructions that are within the alignment. During this phase of planning, engineers also decide on the materials and mode of construction, based on the traffic that it is required to carry after completion.
Drainage of the road is important for allowing it to remain functional at all times, and this is the next step that needs to be taken in road construction. The drains must be led to drainage basins or other waterways that are adjacent to the road alignment. At this time other utilities like power or other that the authorities may need can also be laid down along the road alignment. This can be street lights, communication networks, water, and sewerage lines.
During this work of utilities, the road levels can also be indicated and the needed earthwork to fill or cut to the needed level can be undertaken. This earth must then be properly consolidated with rollers and other equipment so that it meets the design criteria. Layers of gravel, aggregate, or even boulders are then laid down to the designed thickness, with each layer being properly compacted. The number of layers can be anywhere from two to four with each layer of a designed thickness.
The top layer of any road construction is generally of a mixture of asphalt and aggregate that is rolled to give the smooth surfaces that we are used to seeing on roads. Some roads can be made of concrete, which has a longer life and is less prone to deterioration which asphalt roads are often subjected to by the action of the traffic, the sun, and rain.
Care must also be taken during construction of roads, especially highways to allow for cross drainage by building culverts. At times it is also needed to construct bridges and other structures to get over rivers and valleys. Maintenance of roads is another very important aspect of the construction of roads and is essential to see that these channels of communication are always kept open and never disrupted. Quality control and testing during all phases of construction can ensure roads that will give trouble-free service.
