It is important the waterstop be manufactured with quality raw materials, without defects. Many material types and profiles are available for different applications and conditions so the specifier must choose waterstops, preferably with manufacture consultation, appropriate for all the joint conditions.
The three general concrete joint types are:
Construction (i.e. cold) joint—intentional interfaces between adjacent concrete placements created to facilitate construction;
Expansion (i.e. isolation) joint—separates adjacent concrete pours (e.g. walls, slabs, footings, and columns) protecting them from compressive stresses developed by thermal expansion, seismic events, or live load deflection;
Contraction (i.e. control) joints—intentional grooves to create a weakened plane to control the location of cracks resulting from shrinkage of concrete while curing.
To choose a waterstop suitable for the project’s joint-sealing needs, it is important to know the various product types and material compositions. Most types are manufactured exclusively for use in cast-in-place concrete construction joints, while some varieties can also be used with expansion joints. Selected waterstops must accommodate the expected lateral, transverse and shear joint movements as well as the expected hydrostatic pressure.