Stabilization/Solidification of Petroleum-Contaminated Soils with Asphalt Emulsions

Abstract

This paper describes a research study that was conducted to evaluate the design parameters for asphalt pavements and the mechanical properties of cold mix asphalt concrete (CMA) with petroleum-contaminated soils (PCSs). In this research, several commercially available asphalt emulsions were used to make the CMA. Test results showed that the best emulsion type was cationic slow setting (CSS-1h). In a screening test, CSS-1h produced a CMA of high stability and durability values; therefore, it was used to solidify and stabilize six PCSs. Marshall stability tests indicated that the CMA made with PCSs was strong enough to be used in low volume roads (between 500 and 1,400 lb Marshall stability). The wet/dry durability and freeze/thaw durability of the CMA with PCSs showed durability values that were comparable to those of a regular CMA without PCSs. The CMA with PCSs had hydraulic conductivity values comparable to those of asphalt concrete. There was no leaching of U.S. Environment Protection Agency priority pollutants from CMA mixes. Based on the test data, it was concluded that asphalt emulsions could stabilize and solidify PCSs to produce construction material. The unit cost values showed that it is also a cost-effective recycling process. A user manual is provided for the commercial implementation of the process. Based on its simplicity, cost of production, and end use as a construction material, the CMA technology for PCSs surpasses all other treatment, storage, and disposal methods for petroleum-contaminated soils.