Concrete members with a small surface-to-volume ratio are cured by oiling and moistening the forms before casting the concrete member. These forms can be left in place for a prolonged period to prevent moisture loss, and can be wetted if made of a material suitable for wetting. If the forms are removed early, the concrete member is moistened and covered with polythene sheets to maintain moisture. For large horizontal concrete surfaces exposed to dry weather, a temporary covering is suspended above the surface until the concrete sets, after which wet curing is initiated. Wet curing can be achieved by spraying or fogging water over the concrete using a system of nozzles or by ponding the surfaces with water. Also, covering the concrete with moistened sawdust, straw, or saturated moisture-retaining fabrics like wet hessian or cotton mats maintains the contact of concrete with water. Impervious membranes, such as waterproof papers, plastic sheets, or membrane-forming sealing compounds, are also utilized to reduce moisture evaporation from concrete. However, these membranes fail to replace the moisture lost by self-desiccation, as the entry of moisture into the concrete from outside is impossible. Immersion in water is practiced to cure laboratory test specimens of concrete.
Oiling and moistening forms before pouring concrete aid in curing concrete members with a small surface-to-volume ratio.
These forms may be left in place for a specific time and wetted if made of wood, or if removed early, the concrete needs to be moistened and covered using polyethylene sheets.
A covering is suspended above freshly laid large horizontal concrete surfaces exposed to dry weather until the concrete is set, followed by wet curing.
Spraying or fogging water using a system of nozzles and ponding or flooding concrete surfaces with water facilitates wet curing.
Alternatively, covering concrete with moistened sawdust or straw or saturated moisture-retaining fabrics such as wet hessian or cotton mats that are either periodically watered or overlain with a polyethylene film ensures water-concrete contact.
Providing impervious membranes on concrete can minimize the evaporation of moisture but prevent moisture ingress. These can be made of waterproof papers, plastic sheets, or membrane-forming sealing compounds applied manually or sprayed onto damp concrete surfaces.
Curing laboratory test specimens of concrete is achieved by immersing them in water.
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