ETL 1110-3-503
15 Sept 99
h. Paper-industry wastes. The paper industry generates spent sulphite liquor or
lignin sulphonate, which have been used as dust palliatives and for soil stabilization
(Collins and Ciesielski 1994). The Florida DOT has successfully used a small percentage
(8 percent) of bark ash with fly ash as a replacement for portland cement in concrete
mixtures. The bark is burned, along with pulverized coal, and the bark residue ash is
collected. The bark ash/fly ash combination is considered to be equivalent to a Class F
fly ash (Collins and Ciesielski 1994).
i. Petroleum contaminated soils. It is estimated that there are more than 3,000,000
underground storage tanks in the U.S. (Ratz et al. 1997). It is also estimated that
25 percent of all tanks over 2 years old have some leakage and that each leaking tank will
result in approximately 30 to 50 yd3 of contaminated soil. The federal government has
mandated the removal of all underground storage tanks that were constructed without
leak detection and containment systems. Any facility that handles or stores petroleum
materials may be involved with generating petroleum contaminated soil, even if the
petroleum is not stored underground. In one instance, soil contamination was found at a
fuel pump house for an above ground storage facility (Swearingen and Ginter 1998).
Whenever an insitu treatment is not feasible, the soil becomes a possible construction
material. There is a draft Engineering Technical Letter (ETL) concerning the use of
petroleum contaminated soils in pavement construction (ETL 1998).
There are several possible methods available for using the contaminated soils for
pavement construction purposes. These include stabilizing with cement, including them
as aggregate in cold-mix asphalt mixtures, or treating the soil in the heating unit of an
asphalt plant to burn off the contamination. It is generally accepted that a small increase
in the quantity of light petroleum substances would not damage hot-mix asphalt mixtures.
Contaminants are not normally removed during the drying process in conventional hot-
mix asphalt plants because the temperatures achieved are not sufficient to burn off these
materials. However, at least one plant in New Jersey was modified to expose the
contaminated soils to the higher temperatures necessary to burn-off contaminates and
produce hot-mix (Meegoda et al. 1991). Using this type of process, contaminated soils
were used at levels up to 35 percent of the total aggregate in hot-mix asphalt. Depending
upon the method used, contaminated soils have been used for a wide range of paving
applications from subbases to base courses to either hot- or cold-mix asphalt concrete
(Meegoda and Mueller 1993). Petroleum contaminated soils have been used as partial
aggregate replacement in cold-mix asphalt mixtures in several secondary road
applications (Neeley 1990 and Shoenberger 1999). Generally, the asphalt mixtures,
whether cold or hot mix, are evaluated through the compacted mixture having passed
various leachate tests, thus meeting environmental concerns (Meegoda and Mueller 1993
and Shoenberger 1997).
j. Reclaimed asphalt pavement . Reclaimed asphalt pavement (RAP) is being used,
in some form, by practically every state DOT and federal agency (Ciesielski 1995 and
Shelburne and Degroot 1998). The CE has had considerable experience in the use of
RAP material in both hot and cold recycling. The CE guide specification for hot-mix
asphalt contains information for utilizing recycled mixtures containing RAP (CEGS-
B-15
Previous Page
