Abstract
Smart water and wastewater system owners and managers are continually seeking out high quality materials, reliable technology and support to rehabilitate and maintain their conveyance systems cost effectively. Trenchless technology opened up a new world for these owners over 40 years ago with innovations for rehabilitating aging, damaged and deteriorating collection and distribution systems. During this time, many types of trenchless rehabilitation materials and techniques have been developed to first achieve performance demands based upon identified deteriorated conditions of the infrastructure while reducing the economic and social impact with less construction time, less above grade interference, and less damage or disruption to adjacent infrastructure. As time progresses, so has demand for the evolution of materials and processes to lessen environmental, social and economic impact with sustainable solutions for buried infrastructure.
Many trenchless technologies use liquid resin systems, including protective coatings, cured-in-place pipe (CIPP), point repairs and grouting. And, many of the technologies have relied upon polyurethane, ureas, polyester and vinyl ester resins identified with handling advantages, low cost and acceptable mechanical properties. Increased regulatory enforcement has raised concerns related to the use of these styrenatedand isocyanate based resin systems and their potential affect on health, safety and the environment. These concerns, coupled with the demand to increase quality controls for delivery of more consistent performance results exposed a need for the development of safer, cleaner and stronger resin systems to transform buried infrastructure rehabilitation and its impact on minimizing social, economic and environmental disruption while managing high value infrastructure assets.
Although epoxy resins have been used to build, secure, protect and repair all types of infrastructure for the past 75 years, their use in underground rehabilitation was limited due to handling constraints and high cost. Today, chemistry and process technology has evolved that enables their use packaged with mobile equipment removing many restraints found with traditional systems, including a further reduction in carbon footprint.
This paper presents an overview of systems available in the market today, their health and safety characteristics, performance capabilities and delivery mechanisms. Installation technologies are analyzed on their energy efficiencies, environmental impact, performance result consistency, ease of use and cost. The goal was to identify currently available systems; analyze concerns and limitations with these systems; and provide a basis for material selection and installation practices to achieve long-term expectations; while maintaining the utmost protection of humans, animals and the environment.
