The markets: Utility infrastructure (2018)

As noted in the introduction, the repair and replacement of corroded metal infrastructure is a need that grows more dire by the day.

As noted in the introduction, the repair and replacement of corroded metal infrastructure is a need that grows more dire by the day. Corrosion is currently the major cost driver in the maintenance of communication towers throughout the US Air Force inventory. A pressing need for the Air Force to address corrosion-related issues fueled a drive to discover innovative corrosion-resistant materials. The result was a 118-ft communications tower was completely constructed of pultruded composites and installed by the Air Force at Hanscom AFB in Massachusetts. The prototype tower uses fastener-less joining technology where individual components, such as the lattice cross members, “snap” together during the assembly process without the need for metallic bolts. The tower was fabricated by Composite Support & Solutions (CSSI, San Pedro, CA, US) using Ashland (Dublin, OH, US) Derakane vinyl ester resin, designed for pultrusion. The effort earned a Tibbett’s award from the Small Business Admin., which CSSI’s founder and president Clement Hiel received at a ceremony at the White House on Jan. 10. The snap-fit system not only eliminates possible fastener corrosion but enabled tower erection in about one-eighth the time required for a comparable metal tower, tallying commensurate cost savings (see Learn More).

The most pressing need is still in the area of underground pipe. The US Environmental Protection Agency’s (EPA, Washington, DC, US) report, titled State of Technology for Rehabilitation of Water Distribution Systems says, “The impact that the lack of investment in potable water infrastructure will have on the performance of aging underground infrastructure over time is well documented, and the needed funding estimates range as high as US$325 billion in the coming 20 years.”

The 20th Annual Underground Construction Municipal Sewer and Water Survey, conducted by Underground Construction magazine (Oildom Publishing Co., Houston, TX, US) reported in February 2017 that, although 2015 and 2016 had, for the first time in many years, given municipal sewer and water personnel some reason to be optimistic about spending plans for refurbishment of decaying underground pipe systems, 2016 had been a disappointment. Nationwide, sewer and water spending fell 4.2% in 2016 from an anticipated US$19 billion to US$18 billion. Survey information reports that cities hope to spend about US$11 billion in 2017 on new and replacement construction for underground pipes. Sewer comprises US$5.2 billion, water US$3.8 billion and US$2.0 billion of that total. About $8.2 billion is anticipated to be spent on pipe rehabilitation including US$4.7 billion on sewer, US$2.1 billion for water and US$1.4 billion for stormwater.

Survey respondents anticipated a stronger 2017, up 5.2% to US$19.2 billion. Further, they held out hope that the new US administration would come through with a combination of government monies plus leveraging private/public partnerships to fund infrastructure rehabilitation and expansion. The survey also measures impacts from trenchless construction and rehabilitation methods. During budget-crunching times, trenchless rehabilitation gained ground as a cost-effective and successful stop-gap measure to stretch dollars. However, many survey respondents still express the belief that trenchless tends to be more expensive and with 2016’s belt tightening, some cities reverted to simply digging down to problem areas for repairs and dealing with related pavement and social costs. Still, trenchless work has gained growing and irreversible footholds in all aspects of construction and rehabilitation in the US and abroad. The survey revealed that 51.8% of cities prefer to use trenchless for rehab, and for new construction, trenchless is used in about 25% of projects.

Municipal personnel also were asked about their perception of the quality and efficiency of a variety of popular trenchless methods, using a scale of 1 (low) to 5 (high). Achieving the highest performance rating for 2017 are standard water/steam cured-in-place pipe (CIPP) and horizontal directional drilling (HDD) with ratings of 3.8. However, another method of CIPP, ultra-violet light cure, is still new enough to industry that many respondents simply have very limited experience of the technology, so it received a rating of only 2.2. Still, that marked a performance rating increase of 2.0 in 2016.

Filament wound glass/polyester composites have quietly found application in several stages of the most-used seawater reverse osmosis (SWRO) desalination technique (see Learn More). SWRO plants around the world use many miles of corrosion-resistant fiberglass-reinforced polymer (FRP) low-pressure piping as a distribution network, primarily over land, to carry seawater to the plant, to distribute the potable water that is produced, to carry the brine (salt and impurities) back to the ocean, and for internal plant treatment piping and energy-recovery devices. Fiber-reinforced plastic also forms storage tanks and piping used in desalination plants to contain sodium hypochlorite (NaOCl) used in chlorination of desalination process water, and for sulfuric acid — very difficult to store in metal but readily handled in fiberglass/epoxy vinyl ester tanks and piping at ambient temperatures and concentrations below 50%, says Thomas Johnson, corrosion industry manager for resin producer Ashland (Columbus, OH, US). 

 

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