Scarcity of traditional construction materials, price and transport considerations can lead to the development of special pavements. This includes asphalt recycling, use of local materials traditionally considered unsuitable for road building, or alternative binders.
Materials from two or more borrow pits that may each be considered unsuitable, can be combined to achieve a mixed aggregate with good compactability and bearing strength.
Natural occurring deposits of volcanic ash (“pozzolan”) or industrial by-products such as fly ash or blast furnace slag can be used as the main components in binders. These binders are again used to produce high-quality base and foundation layers from fine-grained sand materials.
As alternatives to traditional PCC-based heavy traffic pavements, other special pavements may be structures with combined asphalt/cement concrete surface layers (“semi-flexible” materials) on high-stability bases