An iron process residue aggregate referred to as Iron Rich Material (IRM) was characterized and tested in the laboratory to determine its potential as a highway construction material. Cementmixed and-stabilized products of IRM were subjected to ASTM-based standard tests to determine and compare their strength, permeability, and durability. The potential reuse capacity of IRM was envisioned as aggregate in making stabilized road base, subbase, or subgrade. The aggregate portion of the material was classified as A-1-b by AASHTO and SW by ASTM. This material was stabilized with cement, lime, and fly ash at varying proportions by weight of the total additives. The resulting products were compacted at their predetermined optimum moisture contents and cured. Then samples of the cured products were tested for unconfined compressive strength, unconfined tensile strength, freeze-thaw durability, and hydraulic conductivity. The best results were obtained with cement-stabilized aggregate for which the 7-day unconfined compressive strength was between 102 and 116 kPa (700 and 800 psi) and the unconfined tensile strength was between 14 and 22 kPa (100 and 150 psi). For these specimens the 12-cycle freeze-thaw test resulted in less than 5 percent material loss. The 45-day cured unconfined compressive strengths of the cement admixture stabilized IRM was over 145 kPa (1,000 psi), which is comparable to approximate strength of 138 kPa (950 psi) of soil cement of sandy gravel with 6 percent cement used in base or subbase courses for heavy traffic. The general conclusion of the work was that the particular residue material, IRM, when stabilized with cement and cementitious substances may be a viable aggregate for reuse in construction of road bases.

The subject of resource recovery and reuse of waste materials has gained much attention within the past decade, principally because of the increased number of environmental statutes and regulations that necessitate the minimization of waste disposal (Comprehensive Environmental Response, Compensation and Liability Act, 96-510, 1980). The benefit of reuse of residual materials of industrial processes should be twofold:(a) compliance with regulations, which helps reduce environmental hazard, and (b) added economy. Effective utilization of these materials as an inexpensive alternative for conventional materials can provide much economy provided. that there are no adverse effects to the environment and the created material performs similarly to or equally well as the one it replaces.