PIANC Panama - Agenda

Ali Maher, PhD¹

Robert Miskewitz²

Scott Douglas³

Abbas Sarmad, PE⁴

This paper discusses the feasibility of using a novel sediment solidification/stabilization technique, the Pneumatic Flow Tube Mixing (PFTM), which has been successfully used in Japan for the last decade in large scale reclamation projects utilizing stabilized soft sediments. The study was conducted by the Center for Advanced Infrastructure and Transportation (CAIT) at Rutgers University and its research partners to evaluate PFTM for stabilization and solidification of soft sediments dredged from the New York/ New Jersey Harbor. The study included a comprehensive laboratory investigation aimed at determining the ideal mix for PTFM stabilization, and a pilot scale demonstration of the PTFM technique in the field. Material stabilized during the demonstration was analyzed via unconfined compression tests, needle tests, laboratory vane shear tests, and flow tests in the laboratory and the cone penetration test in the field. Curing times for the samples were 3, 7, 14 and 28 days. The three cement content mixes were 4%, 8%, and 12% by weight (wet weight). Furthermore, samples of raw and stabilized dredged material were evaluated for total constituent concentrations (SVOCs, Metals, Pesticides, and PCBs) via the SPLP procedure. The results of the laboratory and field testing programs demonstrated that PFTM is an effective and efficient technique for solidification/stabilization of soft contaminated sediments from NY/NJ harbor with unconfined compressive strength values from laboratory and field samples averaging about 200 kPa and 75 kPa (8% cement content), respectively, with a uniform field mixture quality. Furthermore, the chemical analysis of the stabilized sediments indicated no detectable mass of SVOCs, PCBs, or Pesticides.

Keywords: dredged soil, pneumatic flow mixing method, unconfined compressive strength, applicability, field test

1. Prof. of Civil Engineering, Dept. of Civil and Environmental Engineering, Rutgers University, 100 Brett Road, Piscataway, NJ 08854-8014, phone (848) 445-2951, email: mmaher@rci.rutgers.edu.
2. Associate Research Professor, Dept. of Civil and Environmental Engineering, Rutgers University, 100 Brett Road Road, Piscataway, NJ 08854-8014, phone (848) 445-0579, email. Email: rmiskewitz@envsci.rutgers.edu
3. Dredging Program Manager, Office of Maritime Resources, New Jersey Department of Transportation, PO Box 837, Trenton, New Jersey, 08625, phone (609) 530- 4770, email: scott.douglas@dot.state.nj.us.
4. Senior Vice President, AECOM, 20 Exchange Place, New York, NY 10017, phone: (917)-945-9026, email: abbas.sarmad@aecom.com. Paper Presenter at the conference