Contents
- How to use this guide
- What “integral waterproofing” does (and doesn’t)
- System types: hydrophobic vs crystalline (PRAH)
- Selection factors by exposure & detailing
- Performance tests & specification language
- Batching, dosing & compatibility
- QA/QC: COA checks, site trials, acceptance
- Troubleshooting: symptoms → likely causes
- RFQ notes (what to include)
- FAQ
How to use this guide
This is a practical decision aid for B2B teams specifying integral waterproofing admixtures for concrete. Use it to align design/spec, ready-mix operations, site QA, and procurement/EHS on (1) what performance is needed, (2) what tests prove it, and (3) what documentation and supply conditions reduce risk.
Important: Integral admixtures improve watertightness by reducing permeability/capillary absorption and, in some systems, supporting microcrack sealing. They do not replace good mix design, placement, joint detailing, and curing discipline. Most leaks come from joints/penetrations or cracking—not “average concrete permeability.”
What “integral waterproofing” does (and doesn’t)
What it does
- Reduces capillary absorption and water transport through the cement matrix.
- Improves durability by lowering water ingress that carries aggressive ions (project-specific).
- Supports watertightness when combined with good crack control and correct detailing.
- Can reduce coating dependency in some below-grade or internal water exposure applications.
What it doesn’t do
- It doesn’t fix poor joint design, missing waterstops, or unsealed penetrations.
- It doesn’t guarantee watertightness if crack widths exceed what the system can tolerate.
- It doesn’t replace curing—poor curing can increase permeability and cracking.
- It doesn’t solve honeycombing/voids from poor placement/compaction.
System types: hydrophobic vs crystalline (PRAH)
Most integral waterproofing admixtures fall into two commercial/technical families. Both can work—when matched to the application.
| Family | Mechanism (high level) | Best fit | Trade-offs / watch-outs | Procurement & supply notes |
|---|---|---|---|---|
| Hydrophobic (water-repellent) | Reduces capillary suction by making pore walls less wettable; lowers water absorption | General below-grade damp conditions, splash zones, non-pressurized water exposure; when you want minimal impact on set/strength | May be less effective under continuous hydrostatic pressure without detailing support; performance is sensitive to w/c ratio and curing | Often liquid admixtures; specify density/solids, chloride content (if relevant), shelf life, and dosing accuracy requirements |
| Crystalline / PRAH (pore blocking / growth) | Promotes formation of insoluble crystals in capillaries that reduce permeability; can support sealing of microcracks over time (conditions dependent) | Water-retaining structures, basements, tunnels, foundations; specs focused on water penetration reduction | Needs curing moisture discipline; may require site trials; can interact with other admixtures if not managed; crack control still critical | Often powder or slurry; packaging controls (bags/drums), moisture protection, and consistent batch blending are critical |
Selection factors by exposure & detailing
The right selection depends on exposure, structural detailing, and construction discipline. Use these factors to shortlist:
Exposure & loads
- Hydrostatic pressure (yes/no, estimated head)
- Wet/dry cycling vs continuous immersion
- Groundwater chemistry (salts, sulfates)
- Freeze-thaw / de-icing salts (region-dependent)
Concrete & design
- Target w/c ratio and cement type
- Crack control strategy (reinforcement, joints)
- Expected crack width tolerance in spec
- Need for low permeability vs low absorption
Construction reality
- Batching accuracy and admixture dispensing
- Curing discipline and scheduling
- Placing method (pump, tremie, slipform)
- QA testing capability on site
Typical application mapping (rule-of-thumb)
- Basements / foundations (damp soil): hydrophobic or crystalline; choose based on pressure and detailing quality.
- Water tanks / treatment structures: crystalline/PRAH systems are common; pair with robust joints/penetrations detailing.
- Tunnels / below-grade with pressure: often crystalline/PRAH + membrane or robust external waterproofing system depending on spec/warranty.
- Precast segments: depends on plant control; integral admixtures can be strong if QA is consistent.
Performance tests & specification language
Waterproofing admixtures should be specified by measurable performance and project acceptance criteria. Many projects reference admixture standards (e.g., EN 934-2 categories or ASTM C494 where applicable) plus additional durability tests.
| What you care about | How it’s commonly evaluated | What to define in the spec |
|---|---|---|
| Water penetration / permeability | Project-specified water penetration tests (lab or field cores); comparative penetration depth reduction | Test method, sample age, curing regime, pressure/head, pass/fail threshold, number of samples |
| Water absorption / capillary uptake | Capillary absorption or sorptivity-type tests; comparative reduction | Acceptance % reduction vs control, curing conditions, reporting format |
| Strength & setting impact | Compressive strength at 7/28 days; set time (if critical) | Allowable deviation vs reference mix; temperature range; batching tolerances |
| Air content / workability | Slump/slump flow retention; air content where relevant (especially freeze-thaw specs) | Target workability window and permitted adjustments (e.g., HRWR compatibility) |
| Crack tolerance (system-level) | Design/spec-driven crack width limits; joint detailing + waterstop requirements | Crack width assumptions, joint waterstop type, penetration sealing method |
Batching, dosing & compatibility
Dosing approach (operational)
- Define dosage by cementitious content (common approach) and document the calculation method for the ready-mix plant.
- Use a site trial / trial mix when the project is critical (watertightness warranty, hydrostatic pressure, complex placements).
- Control water addition on site. Uncontrolled water adjustments can erase permeability gains.
- Mixing energy and sequence matter: especially for powder/slurry systems; ensure dispersion without clumping.
Compatibility (what to confirm)
- Cement type: CEM I/II/III blends, SCMs (fly ash, slag, silica fume) can shift performance and set behavior.
- Other admixtures: water reducers/HRWR, accelerators/retarders, air entrainers—confirm combined effects on slump retention and set time.
- Aggregate moisture & grading: impacts effective w/c and workability, which affects permeability.
- Temperature window: cold/hot weather concreting changes set and curing; adjust plan accordingly.
Commercial note: avoid “spec drift” during construction
Many waterproofing claims happen when the approved mix design changes mid-project (cement source, SCM ratio, HRWR brand, site water addition). Keep a simple change-control rule: if materials change, re-validate the key waterproofing acceptance test.
QA/QC: COA checks, site trials, acceptance
COA / acceptance checks (procurement)
Ask for data you can verify on receipt and that correlates with consistency.
| Category | What to request | Why it matters |
|---|---|---|
| Identity & traceability | Product name, grade, manufacturer, batch/lot, production date | Ensures repeatability and supports claims/warranty documentation |
| Active content | Solids/active %, density (liquids), moisture content (powders) as applicable | Directly affects effective dosage and performance |
| Physical properties | Appearance, pH (if relevant), viscosity (liquids), particle behavior (powders) | Early indicator of off-spec batches or storage damage |
| Contaminants / limits | Chloride content (if required), alkali contribution statement (if required) | Important for reinforcement corrosion risk and durability specs |
| Packaging | Drum/IBC (liquid) or moisture-protected bags (powder); closure/liner details | Prevents degradation and ensures plant handling compatibility |
| Documentation | SDS, TDS, shelf life, storage temperature | Mandatory for EHS approval and stable performance |
Site trial: what to record
- Mix design, cement/SCM sources, admixture brands and dosages
- Batching sequence and mixing time/energy
- Slump/slump flow at discharge and after transport
- Temperature, curing method, and curing duration
- Core extraction plan (if required) and acceptance test schedule
Troubleshooting: symptoms → likely causes
| Symptom | Likely causes | What to check first |
|---|---|---|
| Slow set / delayed strength | Admixture interaction with HRWR/retarder; cold weather; dosing error | Confirm dosage calculation; check temperature; review batching sequence; compare to control mix |
| Segregation / bleeding | Excess water; poor aggregate grading; incompatible admixture combination | Audit water additions; verify aggregate moisture corrections; review HRWR dose |
| Cracking / shrinkage | Poor curing; high paste content; thermal gradients; joint detailing gaps | Review curing plan; check pour sequence and temperature control; confirm joint detailing |
| Leakage at joints/penetrations | Detailing failure (waterstops, sealants, sleeves); movement | Inspect detailing; verify waterstop placement; review penetration sealing system |
| “Meets strength but fails watertightness test” | High w/c; inadequate curing moisture; test regime mismatch; honeycombing | Confirm effective w/c; verify curing; inspect consolidation; confirm test method/age |
RFQ notes (what to include)
- Project type: basement, tank, tunnel, foundation, precast, etc.
- Exposure: hydrostatic head/pressure estimate, wet/dry cycling, groundwater chemistry (if known).
- Concrete details: cement type, SCMs, target strength class, target w/c, placement method.
- Performance requirement: define acceptance tests (penetration/absorption) and pass/fail thresholds.
- Admixture environment: other admixtures used (HRWR, accelerators/retarders, air entrainers).
- Volume & packaging: monthly demand, drum/IBC (liquid) or bag (powder), storage constraints.
- Documentation: SDS/TDS/COA template, compliance statements, shelf life.
- Delivery: country/site location, timing, Incoterms if relevant.
Need a supply-ready option for your spec?
Send your exposure conditions, target test/acceptance criteria, and mix design basics. We’ll propose options (hydrophobic or crystalline) with procurement-ready documentation expectations (SDS/COA), packaging choices, and a site trial checklist.
FAQ
Do integral admixtures replace membranes?
Sometimes they reduce reliance on membranes, but many projects still require external waterproofing and robust joint/penetration systems— especially under continuous hydrostatic pressure, aggressive groundwater, or strict warranty regimes. Think “integral admixture improves the concrete,” while membranes/detailing manage interfaces and movement.
Can crystalline systems seal cracks?
Some crystalline/PRAH systems are marketed for microcrack sealing under moisture availability, but performance depends on crack width, curing moisture, and exposure conditions. Your project should specify crack control assumptions and joint detailing requirements explicitly.
What’s the most common reason waterproofing fails?
Detailing and workmanship: joints, penetrations, honeycombing/voids, uncontrolled water addition, and poor curing. A strong admixture can’t compensate for missing waterstops or inconsistent site practices.
Educational content only. Always follow site EHS rules, applicable project specifications, and the supplier SDS/TDS for safe use. If you share your exposure conditions and acceptance tests, we can help you shortlist compliant, supply-ready options and build an RFQ pack.