Organic Sulphate and Inorganic Sulphide are present in the slimes of sewerage flows and form the Total Sulphide present in the sewerage as following:

    • A fraction of the dissolved Hydrogen Sulphide is released into the sewer atmosphere as a gas.
    • A process of bacterial reduction occurs when the Hydrogen Sulphide, in combination with the other gases, such as Carbon Dioxide, is progressively oxidized, reducing the Ph to the point where it splits off with water molecules to form Sulphuric Acid.
    • The powerful inorganic Sulphuric Acid reacts with hydrated calcium silicates and lime in the cement structure and reduces it to a soft swelling paste.
    • Conditions are optimal for this process of Sulphide attack when there is high biological oxygen demand, presence of sulphates (Common in all water systems), higher ambient temperatures (quickening the kinetics of breakdown and reduction), long detention times (Flat grades – low velocities).

RCC Pipe Corrosion without protection

‘T’ Rib liner protecting RCC Pipe against Corrosion

The solution:

The solution was found in 1947 when the first T-ribbed liner was made in the USA.
Being cast into concrete, at the time of manufacture, the T-ribbed lined pipes were fully protected by mechanically anchored PVC plastic liners.

WHY USE HDPE liner?

Concrete is attacked by Acids and Alkaline. Hydrogen sulphide attack in sewer pipes and structures is a major problem, but also the presence of sulphates and chlorides in soils creates aggressive saline conditions that pose a threat to concrete foundations for all sorts of building works.The evolution of the HDPE liner Linings represents a major breakthrough in physical properties, with elongation at break point being to the order of 600% for polyethylene.

HDPE lining will therefore not crack when placed under stress, like coatings and they will endure for over 50 years in the toughest of service. Abrasion resistance: In comparison to concrete, T-Lock has superior frictional resistance and abrasion resistance and possesses excellent tear strength.

The HDPE liners are smooth. Concrete pipes that are lined with the material therefore have superior hydraulic characteristics to plain pipes and many other materials. This advantage can be translated into savings for the consumer by utilizing smaller diameters of pipes.

Features

  • High Flexible.
  • Available with locking extensions.
  • Provide permanent grip.
  • Excellent resistance against acids and solvents
  • High impermeability to any gas or liquids.
  • Thermoplastic material.
  • Excellent weldability.
  • High jointing strength
  • Resistance to sulfuric acid (H2SO4)
  • High abrasion resistance.
  • Complete protection against Corrosion.
  • Minimum water absorption

Applications

  • Lining of sewage RCC pipes
  • Chemical tanks
  • Basements and Foundations
  • Tunnel and Underpasses
  • Floor Slabs
  • Sewage treatment works
  • Pipeline refurbishment
  • Box culverts
  • Portable water tanks
  • Underground car parks
  • Reservoirs
  • Immersed Tube Tunnel
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