Integral Water Repellent — Absorption and Efflorescence Control

Primary uses

• Capillary water absorption reduction
• Efflorescence control
• Staining resistance support

Applications

• Architectural precast and cast stone exposed to weather
• Hardscape and masonry units
• Units where efflorescence would be a rejection
• Concrete in wet or salt-exposed service

Advantages

• Repellency is distributed through the element rather than sitting on a surface layer that can wear away
• Helps control efflorescence and staining, which are the most common complaints on installed cast stone
• Reduces capillary absorption, which supports freeze–thaw durability in Canadian exposure

Limitations to consider

• Not a substitute for correct mix design, curing and detailing, which govern durability first
• Can affect surface characteristics and the adhesion of coatings or sealers applied later
• Dosage and absorption reduction achieved are established by testing your own mix and element
• Dosage, addition rate, water content and binder proportions are decided by your own mix design and trial batches, not by a catalogue figure. Supplier literature ranges are a starting point for that development work and are not reproduced here as a specification.
• Decorative and architectural work is judged by eye. Colour, gloss, texture and translucency shift with batch, substrate, dosage and finishing method, so approve a physical sample panel made by your own process before a production run and keep it as the reference for later deliveries.
• Mix ratio, pot life, working time, demould time, full-cure schedule, hardness, tear strength, elongation, shrinkage, viscosity and temperature resistance are properties of one specific supplier system. They are never quoted here from memory or by analogy with a similar product; they are read from the supplier data sheet for the exact material offered and confirmed at quotation.

How to choose the right grade

• Start from the problem in the mix — water demand, segregation, set timing, shrinkage or durability — rather than from an admixture category
• List every other admixture already in the mix, because interactions between admixtures are the most common cause of unexpected results
• State the cement and supplementary materials in use, since admixture response is cement-specific
• State whether a surface sealer or coating will also be applied, so adhesion is checked in advance
• Test on production-representative units rather than laboratory cubes, since finish and curing matter
• Mould-making and casting behaviour depends on the pattern, the shop temperature and humidity, the mixing method and the operator. A production-representative trial on your own pattern and in your own shop conditions is the only honest way to qualify a material before a run is committed.
• Exact specification is confirmed against supplier documentation at quotation.

Typical grades

• Liquid and powder products as the supplier offers them
• Products the supplier classifies by chemistry and intended application
• Buyers search this category by grade name, and those names describe what the workshop needs rather than what is asserted here. Which grade a specific offer corresponds to, and what the supplier declares for it, is read from the technical documentation issued for the exact material quoted.
• Materials in this category interact: rubbers, releases, sealers, resins, pigments and fillers can inhibit cure, stain a surface or shorten mould life when they are combined outside the combinations the supplier has tested. State every material already in the process at enquiry so compatibility is checked against supplier documentation rather than discovered on the shop floor.
• Reactive materials age in the container, and moisture-sensitive systems age faster once opened. Order against real consumption rather than against a discount, and confirm the shelf life the supplier states for the exact product and pack.