Concrete pipes for sewage and water systems

Rocla supplies and manufactures a range of sewage and water systems to municipalities and civil contractors throughout South Africa.

Among Rocla’s flagship products are reinforced concrete pipes with highdensity polyethylene (HDPE) lining, which offer sewerage projects the same advantages as conventional concrete pipes or plastic pipes in that they maintain their shape under load and are resistant to acid attack.

Exposed concrete in the joints of a pipeline need to be protected against corrosive gases, and Rocla has designed a HDPE capping strip, which is welded over the joint of the pipe after installation. It is generally 200 mm wide and the same thickness as the lining used in the pipe.

This unique HDPE-lined pipe was recently commissioned for the Polokwane Wastewater Project, and 19 km of HDPE piping was supplied.

Rocla also manufactures reinforced concrete pipes with sacrificial layers. The host pipe may be manufactured from dolomitic aggregate and ordinary Portland cement, or siliceous aggregate and ordinary Portland cement. The sacrificial layer may be from dolomitic aggregate and ordinary Portland cement, or dolomitic aggregate and calcium aluminate cement.

The 300 mm to 600 mm reinforced concrete pipes are manufactured with the Xypex Bio-San C500 admixture. This is a uniquely designed admixture for the integral, long-term protection of concrete in harsh sewerage conditions, which have high levels of H2S that causes microbial induced corrosion in pipelines. The protection is for the full wall of the pipe and eliminates extra joint sealing.

Without the Xypex Bio-San C500 admixture, the exposed concrete in joints of a pipeline needs to be protected against corrosive gases and Rocla recommends joint sealing processes to avoid sewer corrosion activity.

Projects such as the Nellmapius Ext 22 low-cost housing contract near Mamelodi commissioned nearly 3 000 precast steelmesh-reinforced concrete stormwater pipes of various nominal diameters from Rocla, for the 6 km stormwater pipeline being constructed.

Rocla was selected to manufacture and supply all the stormwater (spigot and socket) and interlocking pipes for Waterkloof Quarry – an old, 58 ha landmark situated on the border of Waterkloof Ridge and Monument Park near Pretoria – which was developed into a retirement estate. Rocla’s manufacturing capability helped in meeting the tight deadline associated with the quarry development. For the recent Diepkloof sewer upgrades, 2 715 piping products and associated supplies – comprising RJ pipes, rubber rings, manholes, cover slabs and concrete lids – were sourced from Rocla due to the quality of its manufacturing processes and final product.

Accessories for sewerage and water projects also include pipes with access holes, bends (Rocla can supply custommade bends of up to 30 degrees), spigot and socket pipe systems, manhole chambers with HDPE lining, and reducer and cover slabs.

The Rocla design, engineering and technical team is available for pre-site design, and on-site application advice when required. This way, Rocla ensures that the correct solution is selected and installed correctly.