Upgrading unpaved roads: Road base stabilization using lime and fly ash

A cost-effective alternative to upgrading unpaved roads using asphalt which may cost $100,000 per mile is proposed. In lime-fly ash stabilization, road aggregate is thoroughly mixed with lime, fly ash and water to form a new road base to a depth of five or more inches; this new road base is then compacted and covered with a minimum asphaltic surface layer such as a double chip seal. Guidelines are given for evaluating whether road base stabilization using lime and fly ash (an in-expensive waste product of coal-burning power plants) is an economical alternative to asphalt in upgrading a particular road. Detailed guidelines are presented for estimating the cost of materials for a lime-flyash project as well as a description of the necessary construction and maintenance procedures.