HIGHWAY CONSTRUCTION

The Road Construction Process

The type of road construction used varies from one job to another. The type of construction adopted for a particular road depends on: 

• The volume and nature of traffic to use road,
• The nature of the materials available, 
• The topography, 
• Foundation conditions, 
• Type and availability of construction equipment, and 
• Financing arrangements and timing.

Any road construction job consists of number of basic steps, although the relevant importance and the interaction between these steps will vary from job to job. These steps can be summarized as: 

• Planning, programming and pre-construction activities; 
• Site clearance; 
• Setting out;
• Earthworks; 
• Bridge construction; 
• Drainage structures; 
• Pavement construction; 
• Placement of road surfacing; 
• Placement of road furniture; and 
• landscaping. 

Earthworks

The eventual aim of the earthworks phase of the construction is to position the sub grade underlying the pavement layers in the right location and at the correct level, and to provide drainage. The operations to be performed are: 

• Formation of cuttings by excavating through high ground, 
• Formation of embankments by filling over low ground, formation of embankments by filling overflow ground,
• Shaping the finished surface to design levels, and 
• Excavating for drainage works. 
• The earthworks is often the largest task in the road building process and therefore careful planning and organisation are essential. Speed and efficiency depend very much upon the quantity and types of earth moving plant available earth moving plant available.
• Pavement Construction Pavement Construction
• Cement Concrete Pavements
• Manufacture: ready mixed batching plant. 
• Haulage: agitator truck. 
• Large quantities: site manufacture + normal trucks. 
• Placement: slip-form paver. 
• Compaction: internal vibrators + external screeds.