Utilization of Industrial Wastes in Low-Volume Roads

Abstract

In recent years, applications of marginal materials, also called nontraditional (either natural or waste products), have been considered in road construction with great interest in many industrialized and developing countries. The use of nontraditional materials in road making is based on technical, economic, and ecological criteria. The lack of traditional road materials and the protection of the environment make it imperative to investigate marginal materials carefully. India has a large network of steel plants located in different parts of the country and many more are planned for the near future. Several million metric tons of iron and steel are produced in these plants. However, along with production of iron and steel, huge quantities of solid wastes like blast furnace slag and steel slag as well as other wastes such as flue dust, blast furnace sludge, and refractories are also being produced in these plants. The iron ores in India, although rich in iron content, are high in alumina content also and as such the volume of slag generated is very high. Normally production of 1 metric ton (1 Mg) of steel generates 1 Mg of solid waste. Although the steel industry slags have their own unique properties and are exploitable for road works, they have never been put to use on Indian roads because of a lack of scientific studies conducted on these materials, nonavailability of proper design and construction standards on them, and the absence of data about the long-term behavior of these materials. In the absence other outlets, these solid wastes have occupied several acres of land around plants throughout the country. Keeping in mind the need for bulk use of these solid wastes in India, it was thought expedient to test these materials and to develop specifications to enhance the use of slags in road making, in which higher economic returns may be possible. Exhaustive and detailed laboratory investigations have been carried out at the Central Road Research Institute, New Delhi, India, to develop suitable specifications for construction of low-volume roads. Based on laboratory investigation results, specifications were developed for construction of low-volume roads in different parts of the country. While specifications were being formulated, attempts were made to maximize use of solid wastes in different layers of the road pavement. Postconstruction pavement performance studies have clearly indicated that these waste materials can be used for construction of low-volume roads with twofold benefits: ( a) it will help clear valuable land of huge dumps of slags, and ( b) it will also help preserve the natural reserves of aggregates, thus protecting the environment.