POLYUREA LINERS FOR POTABLE WATER PIPES



Presently there are several renewal options available for various applications, and linings and coatings are mostly used for the renewal of water pipes. These coatings and linings are most commonly used to renew water. Polyurea is one of the most popular coatings and linings.

The lining material is applied to the inner surface of the deteriorated host pipe with a spray method. It can be used to strengthen the structural integrity of the pipe, and also provide a protective coating. This thesis describes the preliminary results from an ongoing testing program in the laboratory intended to study the possibility of a renewal

Potable pipes by using polyurea spray for the lining. This research is focused on forecasting the future of long-term use the behavior in terms of polyurea term behavior of polyurea. The objective in this study was to determine the relationship between polyurea composite and its behavior between strain, strain and time. The results from the tests have been used to help in making predictions about the relationship between strain, stress and time longevity as well as strength and durability of polyurea material. Additionally, it is based on 1,000 hours

Experimental results, curve fitting, and Findley Power Law models were used to predict the long-term term behavior of the materials Power law of Findley accurately predicted the non-linear behavior of the time-creep deformation dependent of this material with acceptable precision. Experimental results found that this material has an excellent combination between strength and stiffness, and could be used in enhancing the structural integrity of plumbing pipes that are potable.




    1. Introduction

      on a level. A perfect corrosion-proof coating and lining should be eco-friendly, safe for workers, strong, and durable enough to shield a small or no substrate to the surrounding environment.

      Trenchless technology is a variety of methods for the rehabilitation of pipelines as well as underground

      pipelines that are not prone to disruption of surfaces and subsurfaces. There are a variety of ways to build pipelines that minimize disruption of subsurface and surface available for rehabilitation of water lines for rehabilitation. The efficiency of this method is dependent on the effectiveness of the physical properties of the pipelining material, and the geometry. There are a variety of factors to be considered

      prior to decide on a specific way of rehabilitation using a lining for the specific project. A liner material should be able to offer protection from corrosion and should be able to guarantee the long-term durability of the product's ability to span gaps. If the pipe is deteriorating liner, it is recommended to offer structural enhancement in conjunction with the host pipe. The rehabilitation plan should be developed in conjunction with the host pipe.

      Based on the analysis of the degree of deterioration of pipes based on the evaluation of deterioration degree. Polyurea is a revolutionary product based on the evaluation of the degree of deterioration created in the 1980's is a the two-component elastomeric liner system with the properties of regenerating the properties of the pipe due to its application.


      Underground infrastructure, a tangible asset that is usually assumed to be a given, as a result of our mental state "out in the distance and away from our the mind" (Najafi and Gokhale 2005). This naive attitude is the primary factor in the degradation of the underground infrastructure. The impact of the deterioration of water lines can cause a lot of damage and can be expensive.



    2. Scope and Objectives

      The primary objective of this study was to establish how long-term strength of three distinct polyurea composites based on tensile as well as flexural properties. This study will it is essential to identify and quantify the impact of stress parameters on both short and long-term effects term-of-life characteristic that is characteristic of liner material.

      The research task consists of analyzing the various mechanical properties in the room
      temperature; performing tests with a similar configuration to determine the right stress for the long-term test; Conducting tests using the liner material, for example, the long-term tensile as well as flexural creep
      as well as formulating results and predicting future properties and the design and life span for polyurea composite.




      Literature Review
      Coatings and Linings
      Pipeline coatings have seen significant technological advances in the last two years.
      decades. Coatings today must function at higher temperatures of operation in the service they cannot be


      injured during handling during construction or operation, caused by soil stress or movement, should provide outstanding corrosion protection. Additionally, coatings must be user-friendly and be
      The coating can be used either in a mill or the field. Coatings are the main method for corrosion protection for the construction of a buried pipeline for the construction of a new pipeline or pipeline rehabilitation. However, it is not necessary when cathodic protection is employed and is considered to be the second protection against corrosion. Thus, today's coatings have to be more secure than their predecessors and will continue to operate under harsh operating conditions and can be used in conditions that are not ideal. The primary substances used in coatings and linings are classified into polymers, cementitious, sheets liners, and cured-in-place liners.



      Polymers - Polyurea
      Polymers are a class of materials composed of covalently-bonded long
      molecules. Polymers are generally divided into three categories that include
      thermoplastics, elastomers and thermosets.

      Figure 1 gives an overview of the different classifications of polymers. Thermoplastics can be classified as linear or branched polymers that are able to be molded and shaped once they are heated. Elastomers are cross-linked
      Polymers that are rubbery and easily stretchable. Thermosets are polymers that are not melted.
      When it is heated.


      1. classification of Polymer (Young & Lovell 1991)


      Today, there are many polymers that are available on the marketplace, all comes with
      distinct properties and their applications. A few of the polymers commonly employed in pipeline industry have distinct properties and applications.
      They include polyurethane, polyurea, epoxies as well as polyester and vinyl ester

      Polyurea Linings are among the most recent technologies within the protective coating industry. They have demonstrated a lot of flexibility and acceptance by the industrial application markets. Due to its outstanding physical chemical as well as mechanical properties and its high efficiency handling capabilities and because of environmental issues, polyurea is gaining popularity in the market the interest has increased in recent years. Polyurea is a two-component elastomer the other one being an isocyanate substance and the other is a polyamine. Polyurea Linings are generally sprayed


    3. 1:1 ratio, however, the ratio may differ based on the formulation of the manufacturer.



      General Properties
      Polyurea possess distinct and unique properties that makes it highly sought-after in
      coating as well as trenchless industries. One of the most distinctive characteristics of polyurea include:

      100% Solids: refers to the absence of solvent that can be used to carry or reduce any coating
      resins. This allows for greater thickness, as well as increase the physical and chemical
      Resistance
      VOC's Polyurea is free of Volatile Organic Compounds as per EPA Method
      8260
      It is also a factor in humidity. Polyurea does not appear to have any effect on water and humidity , but the case
      there are numerous water puddles left inside the pipe. There is also blistering could be there.
      Resistance to Fire and Heat Polyurea coatings offer excellent resistance to distortion caused by heat.
      and as well as sagging. Based on the formulation, certain polyureas have a lower heat deflection
      temperature. If exposed to flames that are constant for 20-30 minutes, polyurea coatings will
      self-extinguish
      Waterproof Systems for waterproofing seamless wood, concrete, metal soil, and many more
      Substrates
      Abrasion Resistance Polyurea is extremely resistant to mechanical force
      like scraping, rubbing or eroding, which causes material to be removed from its
      Surface
      Elasticity: Polymer, being an elastomer, has a linear structure, with a lot less cross-
      linking, which makes it elastic and stretchy.

    1. General Properties

      Polyurea have some unique and outstanding properties which makes it demanding in coating and trenchless industry. Some of the most distinct features of polyurea are:

      1. 100% Solids: Refers to lack of solvent, which can carry or reduce any of the coating
        resins. This helps in achieving additional thickness and increase physical and chemical
        resistance

      2. VOC’s: Polyurea does not contain any Volatile Organic Compounds as per EPA Method
        8260

      3. Humidity: Polyurea is not likely to be affected by moisture and humidity but in reality if
        there are excessive water puddles remaining in the pipe, some blistering may be present.

      4. Heat and Fire Resistance: Polyurea coatings have excellent resistance to heat distortion
        and sagging. Depending on the formulation, some polyureas have a low heat deflection
        temperature. When exposed to constant flame for 20-30 seconds, polyurea coatings will
        self-extinguish

      5. Waterproof: Seamless waterproofing system for concrete, wood, metal, soil, and other
        substrates

      6. Abrasion Resistance: Polyurea has excellent resistance to withstand mechanical action
        such as rubbing, scraping, or erosion, that tends progressively to remove material from its
        surface

      7. Elasticity: Polymer being an elastomer has a very linear structure with much less cross-
        linking which makes it stretchy and elastic.


Table 1.0 presents some of the typical physical properties of polyurea.



Table 1 –Typical Physical Properties of Polyurea


Typical Physical Properties

Description

Tensile Strength

  • Test Method : ASTM D-638

  • Range: up to 4,000 psi

100% Modulus

  • 500 – 1800 psi

Flexural Strength

  • Test Method : ASTM D-790

  • Range: 3200 – 3,500 psi

Flexural Modulus

  • Test Method : ASTM D-790

  • 100,000 to 110,000 psi

Elongation

  • 20 – 1,000 %

Gel Time

  • 2 – 15 seconds

Tear Strength

  • 250 – 600 pounds per linear inch

Application Temperature

  • - 40o F to 122o F

Initial Curing Time

  • 3 – 10 seconds

  • Autocatalytic


3.0 Installation Procedure of Polyurea Lining

The wide use of polyurea in the current trenchless industry as spray coatings has been
made possible through the development of proper installation procedure and application
equipment. The main factor governing an efficient lining is proper installation technique and also
the sequence of activity followed. The effectiveness of a good lining depends on many other
factors such as transportation, temperature changes, resistance to water absorption etc to achieve
an effective application at lower cost. When installed by trained professionals, polyurea offers
tremendous advantages and durability over older technologies. A properly prepared, primed, and
installed polyurea solution provides decades of trouble-free use. Figure 2 illustrates the schematic
process of polyurea lining.

  1. Site Preparation – Site preparation includes preparing the pipeline for cutting and cleaning.
    There are a number of cleaning methods available for cleaning the water pipes, some of
    which are power boring, drag scraping, abrasive pigging, pressure scraping and pressure
    jetting.

  2. Locating Hydrants & Valves – Installation of the polyurea lining material is usually carried
    from valves to valves from upstream to downstream.

  3. Drying - Prior to application the main shall be relatively dry and free from standing water.
    This is achieved by drying with foam swabs, blown through with compressed air.


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