Waste and byproduct utilization in highway construction

The demand for highway materials such as crushed stone, sand and gravel continues to rise while economic sources are often becoming limited. To insure that the best use is made of available materials, an overall materials utilization strategy must be developed that will be coupled with environmental and energy considerations. While recognizing the need for a unified strategy, this study focuses on the utilization of wastes and byproducts in highway construction. Increased usage of wastes and byproducts will both decrease the demand for available materials and help solve many disposal problems.Surveys of highway agencies and literature searches have indicated the potential for waste and secondary product utilization in highway construction. A computerized waste utilization data bank, CERPU, has been developed to store available information for easy retrieval and analysis. This information retrieval system has been used to identify the more promising wastes as a basis for studying their characteristics and usages in the laboratory. Studies on the utilization of wastes and byproducts such as taconite tailings in bituminous concrete, steel slags in bituminous concrete and slurry seals, pelletized blast furnace slag in base stabilization, spent pickle liquors for treating steel slag, and municipal incinerator ash in bituminous concrete, are presented to indicate what is being done and what remains to be done.The potential for waste and byproduct utilization in highway construction is still largely undeveloped. However, it must be understood that these materials can only be used in highway construction when they meet appropriate performance specifications and prove economically viable when environmental factors have been considered.