What are the benefits of pipeline rehabilitation using Cement Lining?

• Save 40 – 80 % over the cost of replacement

• Extend the life of the pipeline for another 50 – 100 years

• STOP corrosion now!

• STOP leaks

• Neutralize any adverse effects of the pipeline on the water

• Increase flow from 15 – 25 %

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How long have Cement Lined Pipes been used?

Beginning in the 1800’s, cement mortar was found to have excellent anti-corrosive properties for use in water lines.  At first, man entry size pipelines were rehabilitated using hand-lining techniques.  Eventually, lining machines were developed which allowed for a consistent lining thickness on the pipe wall for both man entry and small diameter pipe.  Since then cement mortar lining has been used around the world for new pipe and to rehabilitate old lines. 

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How does the cement lining protect the pipe?

The internal cement mortar lining provides protection to the pipeline in two ways.  First, it is a “cement pipe within a steel pipe”, and second, by creating a “Zone of Alkalinity”.   This “zone” between the cement lining and the pipe wall, neutralizes the corrosive properties of the liquid medium and blocks corrosion of the pipe wall.  In effect, the “Zone of Alkalinity” serves as a second layer of defense against internal corrosion.  Unlike other types of internal linings, which allow pipe corrosion to spread down the line once they are chipped or damaged in any spot, the cement lining prevents corrosion from spreading along the pipe wall. 

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What is Autogenous Healing?

Simply stated, autogenous healing is the ability of cement to heal itself.  In the presence of moisture, cement extrudes calcium hydroxide which, upon exposure to the atmosphere, is converted to calcium carbonate (limestone) which seals the crack.  This is the same phenomenon that happens when a broken bone is mended.  Autogenous healing of cement lined pipe is common when the buried pipe is in the presence of moisture, either on the soil side or inside of the pipe itself.  These cracks, when healed autogenously, are stronger than the original cement lining.  Evidence of autogenous healing is a whitish substance forming along the crack line.

Conclusion:  Even though your pipeline has exfiltration problems, it will stop after it is cement lined!

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What is the “Arch Effect”?

Since there is no chemical bond between steel and cement, the lining process relies on the “arch effect” to hold the cement on the upper portions of the pipe prior to curing.

Once cured, this creates “a cement pipe within a steel pipe”.

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 What types of finishes are available?

• Troweled finish – a trowel arm smoothes the lining as the machine exits the line

• “Orange Peel” – a sprayed on finish, which looks like the surface of an orange.

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Does the lining have any strength?

A pressure test was conducted on a length of riveted steel pipe, 48" in diameter and with 1/2" pipe wall thickness. The test section was perforated with numerous test holes from 1" to 6-1/4" in diameter. The holes were fitted with blanks for application of cement-mortar lining, which was applied in a thickness graduating from 1/4" to 1".