How is a road built?

Answer 1

It is built using tarmac. First of all come the planning, preliminary surveying and the requirement and impact assessment phases.

Inter-urban roads are the most complex. A number of criteria must be considered in the selection of a route, mainly based in the communities and geography to be traversed; areas of natural beauty, animal habitats, what will be the impact on people near to the new road; also, what kind of traffic will the road carry, will earthworks, bridges or tunnels be required and if so, what kind of equipment does the geology dictate; straightness of route must be traded against geographical elevation and the need to avoid too much blasting through solid rock and so forth. Then the route is planned on paper. Provision must be made for adequate drainage, protection of the area flanking the road and possibly the laying in of power for warning signs and lighting.

Once the plan receives the requisite local government sign off and approval the work can start. at this stage surveyors will assist the road crew in laying out the route ("staking out"), and provide data for digging trenches and building embankments.

Sources of water and material for the road bed must be located. The materials may come from a quarry or more often from a "borrow pit", in the latter case the road crew must ensure that the scar can be repaired back to its original green condition.

Once this phase is complete the rock hardcore is laid. Rock is crushed, washed and screen filtered. There are various specifications for permissible lump size. The hardcore is laid incrementally and must be compacted thoroughly. Once the hardcore phase is completed the road can be tarred or concreted and the final road dressing and painting and the installation of safety features and road signs can take place.