Utilization of a Pneumatic Tube Mixing Technique for Processing and Stabilization of Contaminated Dredged Material

The following progress report describes the laboratory activities completed for the development of the experimental field program designed to evaluate sediment amendment using the Pneumatic Flow Tube Mixing Apparatus (PFTM) in NY/NJ Harbor. These activities were completed to determine the appropriate field mixing conditions during the July- August 2015 pilot demonstration of the PTFM. It is a novel technology originally developed in Japan for high rate amendment of dredged material for use in man-made islands. The increased rate of processing and uniformity of the stabilized sediment mixture led the New Jersey Department of Transportation (NJDOT) to support a Rutgers University Center for Advanced Infrastructure and Transportation (CAIT) pilot scale field demonstration of the PFTM system in Newark Bay. This effort will evaluate the applicability of PTFM for stabilization of the loose and contaminated sediments native to the Bay for later beneficial use in structural and fill applications. In April 2015 100 gallons of raw dredge material was acquired from the Arthur Kill adjacent to the CME Inc. waterfront. The location is the site of the subsequent dredging operation that will provide sediment for the field scale pilot test. The material was allowed to settle and then was decanted to approximately the water content that will present during PTFM operations. The material was then stabilized with Portland cement at 5 different dosages and 3 different initial moisture contents. The samples were then tested for flowability, short term strength gain using the laboratory vane shear apparatus, and long term strength gain using the Unconfined Compressive Strength Test and the Needle Penetration Test. Cured samples of both the raw and amended material were sent to Precision Testing Laboratory Inc. (Toms River, NJ) for chemical analysis of both raw sediment and leachate via the Synthetic Precipitation Leaching Procedure (SPLP). The preliminary laboratory study has indicated that the primary NJDOT guidance criteria for the July- August 2015 pilot demonstration project will be met using the standard mix of 8% cement by wet weight. Results indicate that: (1) Leachability of potential contaminants is restricted by the stabilization procedure. (2) The raw material will be sufficiently flowable to be processed in the tube mixing system. (3) The stabilized material is predicted to have the minimum required bearing capacity of 3000 lbs/ square foot or 145 kPa.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; Tables;
  • Pagination: 9p

Subject/Index Terms

Filing Info

  • Accession Number: 01637023
  • Record Type: Publication
  • Report/Paper Numbers: CAIT-UTC-053
  • Contract Numbers: DTRT12-G-UTC16
  • Files: UTC, NTL, TRIS, ATRI, USDOT, STATEDOT
  • Created Date: May 17 2017 7:51AM