Chargement…
Chargement…
by Dakhla Aménagement Team
Cracking is the symptom every project owner dreads — and the most misunderstood. Direct answer: the vast majority of concrete cracks come from shrinkage and early-age thermal stress, not from a defective cement. A correct dosage (300-400 kg/m³ depending on the element), a water/cement ratio W/C ≤ 0.50 and 7 days of moist curing prevent most of them; the rest belongs to structural design and joints.
A crack is read on three clues: when it appears, its pattern and its width. A fine surface network in the days after pouring tells of a young concrete evaporating too fast. An open, running crack that widens after loading tells of a structural problem — and calls for the engineer's design calculation, not a coat of render.
| Timing | Typical look | Frequent cause | Severity |
|---|---|---|---|
| First hours | Fine surface threads, 'alligator skin' | Plastic shrinkage (evaporation > bleed) | Cosmetic if treated fast |
| First days | Fine, regular, shallow cracks | Drying shrinkage, poor curing | Aesthetic, watertightness |
| Following weeks | Random mapping + gummy exudations | Possible alkali-aggregate reaction (rare) | Structural — expert required |
| After loading | Opening at the base, running through | Bending, settlement, undersizing | Structural — design calculation |
Cement weighs on cracking from three sides. Dosage first: overdosing 'for safety' raises hydration heat and final shrinkage — overdosing cracks more than it protects. W/C ratio next: every extra litre of water costs 2 to 3 MPa of strength and swells shrinkage — a plasticiser provides flow without that toll. Young-age heat finally: in hot weather, fresh concrete above 30 °C hydrates too fast, thermal gradients settle between core and skin, and the skin cracks while cooling.
A hairline crack is filled with a repair mortar dosed at 350 kg/m³ minimum. A structural crack is handled in two steps: find the cause (settlement, undersizing, thermal shock) then repair — otherwise it comes back. Diagnosis always precedes the render.
For your everyday and demanding works, CPJ 45 (45 MPa) and CPJ 55 (55 MPa) cover the range — free personalized quote, delivered in Dakhla City.
A crack is read on: timing of appearance, pattern, width, evolution. Diagnosis always precedes the render.
Fine (< 0.2 mm), superficial and stable = passive. Open, through, evolving = structural: engineering firm.
Uncured shrinkage, thermal shock, settlement, undersizing? An untreated cause brings the crack back.
Filling with a mortar dosed at 350 kg/m³ minimum after widening, cleaning and dampening the passive crack.
Markers, dates, measured widths: a crack that evolves between two readings changes status — and audience.
Plastic, autogenous, drying shrinkage: three clocks, one main remedy — 7 days of moist curing. The role of dosage and cement fineness.
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Read articleOur team responds within 24h. CPJ 45 on request, CPJ 55 on request. Delivery within Dakhla included.