❄️ Freeze-Thaw Resistance of Concrete
In short
Testing concrete resistance to cyclic freezing and thawing. Direct method (Polish) or CF/CDF (European) with assessment of mass loss and strength decrease. The test is performed according to PN-88/B-06250 pkt. 5.13 / CEN/TS 12390-9:2016; Freezing temperature: -18 ± 2°C (PN-B-06250) / -20°C (CEN/TS). The procedure comprises 11 steps (about 43 days 2 h 40 min–91 days 2 h 40 min in total); it is used for: Design of concrete pavements for roads and airports, Assessment of bridge and viaduct concrete durability, Quality control of concrete in exposure classes XF1–XF4 (PN-EN 206).
At a glance
- Standard: PN-88/B-06250 pkt. 5.13 / CEN/TS 12390-9:2016
- Category: Construction
- Procedure steps: 11
- Total time of stages: 43 days 2 h 40 min–91 days 2 h 40 min
- Freezing temperature: -18 ± 2°C (PN-B-06250) / -20°C (CEN/TS)
- Thawing temperature: +18 ± 2°C (PN-B-06250) / +20°C (CEN/TS)
- Number of cycles: F25–F300 (PN-B-06250) / 28 (CDF) / 56 (CF)
Overview
Freeze-thaw resistance of concrete is a key durability characteristic in the climate of Poland and Central Europe, where concrete structures are exposed to dozens of freeze-thaw cycles annually. Testing involves subjecting concrete specimens to repeated cycles of freezing (at -18°C) and thawing (in water at +18–20°C) and assessing the resulting damage.
In Poland, two main methods are used. The direct method (Polish) per PN-88/B-06250 involves subjecting 100×100×100 mm cubic specimens to a specified number of freeze-thaw cycles (F25, F50, F100, F150, F200, F300) and comparing their compressive strength with reference specimens (stored in water). Concrete is frost-resistant if strength decrease does not exceed 20% and mass loss does not exceed 5%.
The European method CEN/TS 12390-9 (CF/CDF) assesses resistance of concrete surface to scaling under frost action. In CF method, specimen is immersed in deionized water and subjected to 56 freeze-thaw cycles. In CDF method — in 3% NaCl solution and 28 cycles. Assessment criterion is surface mass loss (scaling) in g/m² — typical requirement: ≤1500 g/m² after 28 CDF cycles.
Concrete freeze-thaw resistance depends mainly on air void structure — key parameter is spacing factor L̄ (≤0.20 mm) and air content (4–7%). Therefore, air-entraining admixtures are used in frost-resistant concretes, creating fine, uniformly distributed air voids acting as pressure buffers for freezing water.
Method principle
Direct method (PN-B-06250): Water-saturated concrete specimens are frozen in freezing chamber at -18 ± 2°C for 4 h, then thawed in water at +18 ± 2°C for 4 h (1 cycle = 8 h). After specified number of cycles (e.g., 150), compressive strength is compared with reference specimens. CDF method (CEN/TS 12390-9): Specimen surface is immersed in 3% NaCl solution to 3 mm depth. Cycle: freezing from +20°C to -20°C over 12 h and thawing to +20°C over 12 h. After 7, 14, 21 and 28 cycles, scaled concrete particles are collected and weighed.
Applications
- Design of concrete pavements for roads and airports
- Assessment of bridge and viaduct concrete durability
- Quality control of concrete in exposure classes XF1–XF4 (PN-EN 206)
- Testing of precast concrete elements exposed to frost (paving blocks, curbs)
- Assessment of air-entraining admixture effectiveness
- Expertise of frost damage to existing structures
- Testing of architectural concrete exposed to atmospheric conditions
Key parameters
| Parameter | Value |
|---|---|
| Freezing temperature | -18 ± 2°C (PN-B-06250) / -20°C (CEN/TS) |
| Thawing temperature | +18 ± 2°C (PN-B-06250) / +20°C (CEN/TS) |
| Number of cycles | F25–F300 (PN-B-06250) / 28 (CDF) / 56 (CF) |
| Specimen dimensions | 100×100×100 mm (PN-B-06250) / 150×150×50 mm (CDF) |
| Criterion (Polish method) | Rc decrease ≤ 20%, mass loss ≤ 5% |
| Criterion (CDF) | Scaling ≤ 1500 g/m² after 28 cycles |
Standard
- Standard number
- PN-88/B-06250 pkt. 5.13 / CEN/TS 12390-9:2016
- Title (PL)
- Beton zwykły — Mrozoodporność / Badania betonu stwardniałego — Część 9: Odporność na zamrażanie-rozmrażanie — Złuszczanie
- Title (EN)
- Normal concrete — Frost resistance / Testing hardened concrete — Part 9: Freeze-thaw resistance — Scaling
Step-by-step procedure
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Specimen preparation
Prepare 12 specimens 100×100×100 mm (Polish method) or 5 specimens 150×150×50 mm (CDF). Cure 28 days in water 20 ± 2°C.
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Series division
Polish method: 6 frozen + 6 reference specimens (in water). CDF method: 5 test specimens + reference specimens.
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Water saturation
Polish method: immerse specimens in water for 7 days. CDF method: seal sides with resin/foil, capillary saturate specimens in 3% NaCl.
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Initial measurements
Weigh all specimens. CDF method: measure container mass with solution. Record dimensions.
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Cyclic freezing-thawing
Polish method: 4 h freezing (-18°C) + 4 h thawing (water +18°C) = 1 cycle. CDF method: 12 h cooling to -20°C + 12 h heating to +20°C.
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Intermediate control (CDF)
After 7, 14, 21 and 28 cycles: collect scaled particles from solution by filtering, dry at 105°C, weigh. Replenish solution.
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Specimen inspection (Polish method)
After every 25 cycles: visual inspection — no cracks, delamination. Weighing — mass loss ≤5%.
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Final strength testing
Polish method: after reaching target cycle number — test compressive strength of frozen and reference specimens.
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Calculations
Polish method: ΔRc = (Rc_ref - Rc_frozen)/Rc_ref × 100% ≤ 20%. CDF method: scaling Σmn/A [g/m²] ≤ 1500 after 28 cycles.
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Frost resistance classification
Polish method: class F25–F300 = number of cycles without damage. CDF method: frost-resistant/non-frost-resistant per 1500 g/m² criterion.
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Documentation
Report: concrete composition, curing conditions, test method, cycle number, intermediate results, strength, mass loss, classification.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Freezing chamber (laboratory freezer) | Weiss WK3 340, CTS C-40/350, Binder MK 240 — range to -30°C | 40 000–150 000 PLN |
| Thawing tank with thermostat | Steel, thermostated 18–20°C, capacity min. 100 L | 3 000–10 000 PLN |
| Compression testing press | Controls Automax, Matest C070 — for comparing Rc of frozen and ref. specimens | 80 000–250 000 PLN |
| Laboratory balance 10 kg | Radwag WLC 10/A2, accuracy 0.1 g | 2 000–5 000 PLN |
| CDF containers (European method) | Steel or plastic, with sealing frame, per CEN/TS 12390-9 | 200–600 PLN/pc |
| Laboratory oven | POL-EKO SLW 115, for drying scaled particles | 5 000–12 000 PLN |
| Thermometer with data logger | Testo 176 T2, Pt100 sensor, 10 min recording — chamber temperature monitoring | 1 500–4 000 PLN |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Sodium chloride (NaCl) | 7647-14-5 | For preparing 3% solution in CDF method, analytical grade purity |
| Deionized water | — | For CF method and for preparing NaCl solution in CDF method |
| Epoxy resin | — | For sealing CDF specimen side surfaces (only test surface exposed) |
| Aluminum foil | — | For wrapping CDF specimen sides as moisture barrier (alternative to resin) |
| Butyl rubber (gasket) | — | For sealing CDF container edge with specimen |
Health and safety (OHS)
- Freezing chamber — frostbite risk, use thermal gloves and protective clothing
- Handling frozen specimens — slippery, fall and bruise risk
- NaCl solution — corrosive to low-grade stainless steel, protect equipment
- Epoxy resin — sensitizing, use gloves and ventilation
- Compression press — crushing hazard, fragments during specimen failure
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-88/B-06250 pkt. 5.13 / CEN/TS 12390-9:2016 — “Normal concrete — Frost resistance / Testing hardened concrete — Part 9: Freeze-thaw resistance — Scaling”.
How does this method work?
Direct method (PN-B-06250): Water-saturated concrete specimens are frozen in freezing chamber at -18 ± 2°C for 4 h, then thawed in water at +18 ± 2°C for 4 h (1 cycle = 8 h). After specified number of cycles (e.
What is the measuring range and accuracy?
Freezing temperature: -18 ± 2°C (PN-B-06250) / -20°C (CEN/TS); Thawing temperature: +18 ± 2°C (PN-B-06250) / +20°C (CEN/TS); Number of cycles: F25–F300 (PN-B-06250) / 28 (CDF) / 56 (CF); Specimen dimensions: 100×100×100 mm (PN-B-06250) / 150×150×50 mm (CDF).
How long does the test take?
The times given for the individual stages add up to approximately 43 days 2 h 40 min–91 days 2 h 40 min. The procedure comprises 11 steps.
What equipment is required?
Freezing chamber (laboratory freezer), Thawing tank with thermostat, Compression testing press, Laboratory balance 10 kg, CDF containers (European method), Laboratory oven, Thermometer with data logger. Indicative cost of the core instrument (Freezing chamber (laboratory freezer)): 40 000–150 000 PLN.
Where is this test used?
Design of concrete pavements for roads and airports; Assessment of bridge and viaduct concrete durability; Quality control of concrete in exposure classes XF1–XF4 (PN-EN 206); Testing of precast concrete elements exposed to frost (paving blocks, curbs); Assessment of air-entraining admixture effectiveness; Expertise of frost damage to existing structures; Testing of architectural concrete exposed to atmospheric conditions.
What safety precautions apply?
Freezing chamber — frostbite risk, use thermal gloves and protective clothing; Handling frozen specimens — slippery, fall and bruise risk; NaCl solution — corrosive to low-grade stainless steel, protect equipment; Epoxy resin — sensitizing, use gloves and ventilation; Compression press — crushing hazard, fragments during specimen failure.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-B-06250 / CEN/TS 12390-9.