Crushed Stone in Road Construction: Layers and Fractions

A quality road is a layer cake where each layer performs its function. Crushed stone is the main ingredient of this cake.

Pavement Layers

1. Lower base layer

A coarse fraction of 40-70 mm is used. It creates a rigid skeleton for the road and provides drainage.

2. Upper base layer

A 20-40 mm fraction is applied. It wedges the lower layer, creating a flat and durable surface.

3. Asphalt Concrete

Fine crushed stone 5-20 mm (cuboid) is added to the mixture itself. It provides the adhesion of components and the wear resistance of the coating.

Requirements for Road Crushed Stone

For roads of category I-II, only granite crushed stone of a grade not lower than M1200 is allowed to be used.

The most important parameter is flakiness. Cuboid crushed stone (flakiness up to 15%) compacts better and lasts longer.