Membrane curing of concrete is done by:
Correct Answer: D. Applying paraffin or resin-based liquids on the surface
📚 Detailed Explanation: Membrane Curing — Chemical Sealing of the Surface
Why D (paraffin or resin-based liquids) is correct: Membrane curing is a dry method of curing. Instead of adding water to the concrete surface, a waterproof liquid compound is sprayed or applied. Once it dries, it forms an impermeable membrane that traps the existing mix water inside the concrete, preventing evaporation and allowing hydration to proceed.
Membrane Curing Compounds
| Type | Material | Application |
|---|---|---|
| Wax-based | Paraffin wax emulsion | Sprayed on freshly finished surface; white or clear |
| Resin-based | Acrylic, styrene-butadiene resin | Sprayed; forms clear, UV-stable film |
| Bitumen-based | Bitumen emulsion | Brushed or sprayed; dark colour |
| Polyethylene sheeting | Plastic film | Laid over fresh concrete; sealed at edges |
All Curing Methods Classified
| Category | Method | Principle |
|---|---|---|
| Wet curing | Ponding | Adds water continuously |
| Spraying / fogging | Adds water intermittently | |
| Wet cloth / hessian | Keeps surface moist | |
| Membrane curing (dry) | Paraffin / resin compound | Seals surface; prevents moisture loss |
| Plastic sheeting | Physical barrier against evaporation | |
| Accelerated curing | Steam curing | Elevated temperature + moisture; for precast |
- Membrane curing = applying paraffin or resin-based liquids to seal the concrete surface.
- No external water added; existing mix water is retained for hydration.
- Ideal for large flat areas (roads, airfields) where wet methods are impractical.