Title: Fly Ash Containing Petroleum Contaminated Soils

Author(s): A. Samer Ezeldion, David A. Vaccari, and Robert T. Mueller

Publication: Symposium Paper

Volume: 132

Issue:

Appears on pages(s): 693-712

Keywords: compressive strength; concretes; flexural strength; fly ash; impurities; permeability; site cleanup; soils; solidification; stabilization; wastes; waste treatment; Materials Research

DOI: 10.14359/2173

Date: 5/1/1992

Abstract:
With more than 3 million underground storage tanks located throughout the U.S., and mass oil drilling, production, and transportation, leaking problems generate large quantities of petroleum-contaminated soils (PCS). With the limited availability of solid waste disposal facilities, research is needed to investigate viable reuse options for PCS. Paper presents an attempt to apply stabilization/solidification techniques to PCS to bind the hydrocarbons in a structure formed by cement, fly ash, and aggregates to produce a construction material suitable for bulk applications. An experimental program was developed to examine the potential for using PCS as a fine aggregate replacement in concrete. Two PCS types with different levels of heating oil contamination were investigated (0.11 and 0.66 percent contamination concentration by weight). For each soil type, nine mixtures were obtained by replacing sand with PCS (PCS-sand ratio of 10, 20, and 40 percent by weight) and Class C fly ash with cement (fly ash-cement ratio of 10 and 20 percent by weight). Compressive and flexural strengths, permeability (hydraulic conductivity), and leachability of benzene-to-water tests were conducted. Results indicate that the addition of PCS reduces both the compression and flexural strengths of concrete. However, the obtained strength is adequate for structural applications. Concrete containing higher PCS-sand replacement ratio develops lower strength. That strength loss increases with higher contamination concentration. Given longer curing time, the fly ash presence can reduce such loss. The permeability coefficient of PCS concrete is slightly higher than control. Fly ash addition yields a more impermeable PCS concrete. For both soil types, at 40 percent PCS-sand replacement ratio, the leachability of benzene was nondetectable after 24 hr and 10 days of casting.