Durability Testing of Composite Materials for Reclamation Pipelines

Project ID: 9777
Principal Investigator: Jay Swihart
Research Topic: Repair and Maintenance
Funded Fiscal Years: 2016, 2017 and 2018
Keywords: None

Research Question

The purpose of this study is to determine durability testing and quality assurance methods to facilitate use of
composite materials on Reclamation pipeline projects. Laboratory durability testing would aid Reclamation staff in
developing performance standards during the pipeline design phase. Quality assurance methods would be used by
field personnel during installation to ensure a quality product is delivered. This research would primarily be
directed toward use of fiberglass pipe and fittings, but would also be extended to tanks and structural
components (vaults, manholes, etc.).

Need and Benefit

Fiberglass pipe is typically more expensive than other pipe options (concrete, steel, and PVC) but has higher
strength values and excellent chemical resistance. Therefore, fiberglass pipe is cost competitive in high-pressure,
large-diameter applications, requiring increased chemical resistance. Composite pipe often has lower installation
costs than steel or concrete pipe due to its lower weight, which can make it a cost-competitive option from an
overall project perspective. In addition, composite pipe is a corrosion resistant alternative to steel pipe, offering
superior performance in certain soil environments and design situations.
In the 1980's, Reclamation had a series of pipe failures with RPM (Reinforced Plastic Mortar) pipe in diameters
ranging from 24- to 48-inches. Pipes were typically buried in the right-of-way on rural roads. Failures were
catastrophic (pipe burst) leading to significant concerns to public safety. Reclamation placed a moratorium on RPM
pipe while the reasons for premature pipe failure were investigated. Reclamation concluded that the
manufacturing process was highly variable. The glass fibers were wrapped around a steel mandrel and alternated
with layers of resin and sand filler. The RPM pipe was subject to manufacturing flaws because each pipe section
was essentially fabricated by hand and highly dependent on the skill of the manufacturing technician. The hand
lay-up process also resulted in resin voids within the pipe wall profile. These voids made the RPM pipe highly
sensitive to construction impact damage – far more sensitive than other pipe options.
Recent advances in composite pipe technology seem to have addressed the previous concerns with RPM pipe.
Modern composite pipe is centrifugally-cast using chopped or continuous fibers. Manufacturing is computer
controlled resulting in a consistent product. The centrifugal cast process results in a dense pipe wall with
complete resin saturation of the glass and sand filler. This project aims to investigate the current composite pipe
products via in-house testing in the above-mentioned challenge areas. In addition, quality assurance procedures
will be developed to evaluate as-received pipe in the field. This research could make available an economically
competitive class of pipe with superior corrosion resistance that is currently not considered for Reclamation
projects.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Durability Testing of Composite Materials for Reclamation Pipelines (final, PDF, 1.6MB)
By Jay Swihart
Publication completed on May 01, 2016

This report documents Reclamation's history with RPM fiberglass pipe, reviews the available literature for recent developments, and identifies additional research needs. Between 1967 and 1984, Reclamation installed about 100 miles of Techite RPM pipe. Reclamation began experiencing RPM pipe failures within 10 years, while other users experienced failures within 5 years. The main difference was more stringent inspection and quality assurance both at the factory and at the jobsite. Investigations identified several inherent weaknesses in the design, manufacturing, and installation of RPM pipe. After several lawsuits, Techite RPM pipe was removed from the market in the mid 1980's. In 1990, Reclamation formally discontinued use of all fiberglass pipes while known deficiencies were addressed. In 1997, Reclamation lifted the ban on all fiberglass pipe meeting the newly established AWWA C950-95 "Fiberglass Pipe Standard" and AWWA M45-95 "Fiberglass Pipe Design Manual". However, each client retained the ultimate authority to select the pipe options best suited for their needs. Therefore over the last 30 years, fiberglass pipe options were rarely (if ever) included in Reclamation specifications. Recently, Reclamation began including the RPM fiberglass pipe option on large jobs such as Navajo-Gallup (NM) and East Low (WA). This report identifies key issues that still need to be addressed.

Durability Testing of Fiberglass Pipe for Reclamation Pipelines (final, PDF, 4.3MB)
By Kelly Ramaeker and Michael T. Walsh
Report completed on September 30, 2018

This research product summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20