EXPANSION AND SEAL JOINTS FOR CAST-IN-SITU REINFORCED CONCRETE
The joints shown are high quality flexible, stabilized PVC profiles for use as take up joints, or vertical and horizontal expansion joints in reinforced concrete guaranteeing a perfect watertight seal even under pressure, or where there are air gaps or foreign bodies in the joints required when building dams, foundations, canals, tonnels and similar. The PVC used guarantees a high ageing resistance, as well as excellent resistance to alkalies, brackish water, and acidic environments. Should the structure be continuously exposed
to hydrocarbons or vegetable based alkalies, a special type of PVC can be supplied.
The various types of waterstop joints are available to resist the high stresses the material will be subjected to during settlement of the building, as well as it’s normal expansion and contraction due to temperature fluctuations.

INSTALLATION
If being used as a take up joint, after the first part of the structure has been cast the next part will be cast against the seal, taking care that there is no air trapped, and that the seal is flat and correctly positioned. If, however, an expansion joint is being formed, a seat should be prepared in the first part of the structure. The next stage is to fill the gap with rot-proof elastic material to fill the bulb required, or to the desired size.
If the joint is to be a waterstop situated on the outside of the structure, the joint must be nailed in position if the shuttering is wooden. If the shuttering is metal, then the seal must be
anchored to the reinforcing bars using soft wire every 30 to 50 cm, so that the seals are not moved or misshapen by the pressure of the concrete beingpoured, or by vibrations during
compaction.
Joints in the seal material are formed by heat welding the two extremities using a hot air gun or a special blade heater element at 200°C.

SIZING
The width of the waterstops must be the same as the thickness of the reinforced concrete wall. For example: for a 200 mm thick wall a 200 mm wide waterstop seal will be used.

JOINTING OF THE ELEMENTS
The various profiles can be jointed on site by welding the extremities using a Leister welder or a hot blade, “thermal sword”.
If using a hot blade proceed as follows:
- The edges of the joint must be perfectly squared off
- Insert the hot blade between the pieces to be jointed and melt the material for approximately 2 mm each side, then press the edges together.
- Hold the pieces in position for approximately 2
minutes but then wait until the joint has cooled before handling.