Compaction characteristics of contaminated soils-reuse as a road base material

Contaminated soils generated from leaking underground storage tanks (USTs) sites are classified as solid waste or non-hazardous waste. Since petroleum contaminated soils are solid waste they cannot be used as clean fill material. A sub-base of a major freeway in New Jersey was built with petroleum contaminated soils. The petroleum soil was appropriately contained to prevent leaching of petroleum products. In order to understand the compaction behavior of petroleum contaminated soils, an extensive laboratory study was conducted. The following conclusions were drawn from the test results. When the soils are contaminated with non-polar organic liquids, due to the lubricating action, there is an improvement in compaction characteristics. This is not continued beyond the oil content value corresponding to the situation where all the soil particles are coated with oil. When the soils are contaminated with polar organic liquids, besides the above lubricating action, the soil structure tends to be dispersed. The dispersed soil structure produced low maximum dry density. However, if the pore liquid viscosity was high the soil structure effect is masked to improve the compaction characteristics. A 2.5% glycerol content improved the compaction characteristics of all the clayey soils tested.