Abstracts
Low Permeability Backfill for Utility Trenches in
By Parry, James
Wisconsin Department of Transportation
3502 Kinsman Blvd
Madison, WI 53707
PH: 608-246-7939
FAX: N/A
E-Mail: james.parry@dot.state.wi.us
Problem Statement
In some cases on DOT projects, the decision is made to leave certain contaminated soils in place. If utility trenches are to be located adjacent to or through these contaminated sites, using conventional granular backfill would allow rapid spread of the contaminants along the trench.
Research Objectives
For these situations, the WisDOT Bureau of Environment requested development of specifications for low permeability backfill that would provide better containment of contaminants.
Research Method
N/A
Product
The mixtures under this study are controlled low strength materials (CLSM), also known as flowable fill. Components of the mixes include cement (25-50lbs/cy), fly ash (400-600 lbs/cy), sand (PCC gradation) and water. Desired properties of the final mix proportions for specifications include: Minimum flow (ASTM D6103) value of 9 inches, Maximum ultimate compressive strength (ASTM D4832) of 300 psi to ensure that material can be excavated with backhoe in future, and Maximum permeability (ASTM D5084) of approximately 1 x 10(E-7) cm/s (similar to landfill clay)
Completion Date: Dec 31, 2002
Category: Materials
Keywords: contaminated soil, continuously reinforced concrete, low strength materials, pavement performance,
Date Posted: Nov 13, 2001
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