Cement mortar lining

Fig. 5-13 Cell current in a pipe with cement-mortar lining anode is an uncoated ring, tapwater at 15°C.

Figiue 4.15 shows the basic structure of cement-based materials, exemplified by a cement-mortar lining. The binder consists of hydrated cement produced by reacting water with anhydrous cement, which contains calcimn silicates and calcium aluminates in various proportions. 

Generally, concrete used for water treatment plant pipes, water tanks, and filters is made using (ordinary) Portland cement, whereas cement-mortar linings can be made of diflerent types of cements, such as Portland cements, blast furnace cement or the non-Portland calcium aluminate cement. Each type of cement has a typical composition. Table 4.14 gives the typical composition of the primary cements used for manufacturing pipe. 

Tested samples were duetile iron pipe with cement mortar lining, of 150 mm internal diameter. 

Conroy, P.J. and Oliphant, R. (1991), Deterioration of water quality. The effects arising from the use of factory applied cement mortar linings, WRC Report NDoE 2723-SW. 

TABLE 4.32 Estimated Costs for Water Pipe Rehabilitation by Cement Mortar Lining... 

S] AWWA Standard C104, Cement-Mortar Lining for Ductile Iron Pipe and Fittings for Water, AWWA, Denver, CO. 

In the case of cemented materials, such as, for example, the cement mortar linings on steel and cast iron pipes, according to [9] the following data must be known ... 

Because of the disadvantages described, the thin coating of tar pitch was replaced by a cement mortar lining [26], Ductile cast iron pipes [27] with a cement mortar lining (CM lining) have since been used exclusively in Germany since the midseventies. 

Eigenschaften und Bewahrung von Zementmortelauskleidungen in gufieisemen Dmckrohren (Properties and rehabihty of cement mortar linings in cast iron pressure pipes) (in German) fgr Information (1969) p. 16 [26 Anonymous... 

External and internal corrosion resistance of the pipe material itself and the sealing material or the external and/or internal corrosion protection External corrosion protection according to DIN 30674, Part 3 or Part 1, 2 or 5. Internal corrosion protection with cement mortar lining according to DIN 2614 or with a special lining. 

Maintenance suitability Investigations with respect to the influence of high-pressure water sprays on the cement mortar lining of the ductile cast-iron pipes showed that there was no damage caused by commonly used nozzle heads and flushing pressures up to 170 bar. 

It is recommended to use ductile (nodular) cast iron instead of gray cast iron (brittle). Ductile iron pipe with a cement mortar lining has given excellent performance. 

---