Cement mortar lining

Cement mortar lining is a protective technology in which cement mortar is sprayed or centrifugally poured on the inner wall of steel pipes or ductile iron pipes. CML can effectively prevent the conveyed medium from coming into direct contact with metals, thereby preventing corrosion, scaling and improving the efficiency of fluid transportation.

Cement mortar lining is widely used in water supply pipeline systems, fire protection systems, sewage and seawater transportation pipelines, industrial circulating water systems and other fields. It is a protective measure that is both economical and reliable.

The production process flow of Cement mortar lining

1. Surface pretreatment
Before construction, the inner wall of the steel pipe needs to be sandblasted for rust removal, usually requiring a cleanliness standard of Sa 2.5 grade to remove the surface oxide scale, oil stains and impurities, ensuring that the mortar has good adhesion.

2. Spraying and Pouring
The cement mortar is evenly applied to the inner surface of the museum by centrifugal pouring or spraying process to form an inner lining layer with a thickness of 3-6mm. This process can ensure that the lining is dense, uniform and closely bonded to the substrate.

3. Curing and Inspection
After the construction is completed, the inner lining needs to undergo curing treatment in a constant temperature and humidity environment. Subsequently, thickness inspection, adhesion test and appearance check should be carried out to ensure there are no cracks, bubbles or delamination.

The material composition and protection principle of cement mortar

Material composition and proportion

Basic materials: ordinary Portland cement, medium sand, water and admixtures (such as water reducing agent, water repellent).
Proportioning requirements: The typical weight ratio is cement: sand: water =1:1.2- 1.4:0.35 -0.45. Admixtures need to be adjusted according to the environment.
Special modification: Some projects use acrylic emulsion mortar (modified mortar with acrylate copolymer emulsion) to enhance crack resistance and bonding strength.

Protection principle (Dual protection mechanism)

The principle of physical isolation: When cement mortar hardens, it forms a dense and firmly adhered protective layer. This protective layer can prevent direct contact between water, oxygen and dissolved salts and the metal substrate, avoid electrochemical reactions inside the water pipe, and fundamentally block the formation of corrosion cells. At the same time, it can provide a smooth inner wall, reduce fluid friction and improve transportation efficiency.

The principle of chemical passivation: Cement mortar is a strongly alkaline material. When it comes into contact with the metal surface, it forms an extremely thin oxide passivation film (Fe₂O₃·xH₂O) on the surface of the steel. This film can prevent metallic iron from further reacting with water and oxygen. Even if tiny cracks occur, they can self-heal or re-passivate in a highly alkaline environment.

The main advantages of Cement Mortar Lined pipes

Cement mortar lined steel pipes have outstanding technical performance and economic advantages:

Excellent anti-corrosion performance - prevents metal from coming into contact with the medium and effectively inhibits corrosion.
Low fluid resistance - smooth inner wall, low friction coefficient, and higher flow rate.
Long service life - low maintenance cost and can operate stably for a long time.
Green and environmentally friendly - non-toxic and harmless, suitable for drinking water delivery systems.
Good mechanical properties - It has excellent impact resistance and pressure resistance.

Implement standards and quality control

CML products are usually produced and tested in accordance with international standards, including:

AWWA C205 - Standard for Cement Mortar Lining and Coating of Steel Water Pipes
ISO 4179 - Specification for Cement Mortar Lining of Ductile Iron Pipes
EN 10298 - Standard for Cement Mortar lining of Steel pipes

These standards clearly stipulate the proportion of raw materials, construction methods, inspection approaches and performance requirements, ensuring the consistency and durability of the products.

Typical application fields of Cement Mortar Lining

Cement mortar linings are widely used in both municipal and industrial fields, including

Urban water supply and drinking water delivery systems
Sewage and reclaimed water treatment network
Fire water supply system
Seawater desalination and cooling circulation system
Industrial medium conveying pipelines

Conclusion

Cement mortar lining is a mature and efficient pipeline protection technology. With its excellent anti-corrosion performance, smooth fluid characteristics and long-term stability, it is widely used in various water supply and industrial pipeline systems worldwide.

Read more : Ceramic lined steel pipe VS Cement lined steel pipe or Concrete lined steel pipe VS Cement lined steel pipe