Road Base

Works on the road base or soil are the most expensive and laborious part of road construction. The aim of road base is to provide stability. The survival of the surface layer is dependent on the roadbed. Hence, it is extremely important to discharge all excess water from the road base. A well-designed and built roadbed can last for decades without needing extensive reconstruction. 

A well-constructed road base consists of compacted sand layer and gravel or crushed stone on top of it. Several layers of gravel and/or crushed stone might be used on sand, depending on the intensity of traffic.

This may sound strange, but in Estonia, the question of the necessity of a roadbed only arose in the mid-1930s, taking after the United States and Germany. During that time, building a roadbed meant removing soil and filling it with a thin (only 100–200 mm) layer of sand or gravel. This procedure did not help avoid frost heaving and sloping. In Estonia, roads for cars were built in such a manner until the end of the 1950s.

Since then, the roadbed has gained more and more attention. The change came with the mechanisation of soil works, which made the process easier and faster. Excavators, dump trucks, heavy-duty graders and other such machines came into use.