Concrete Curing Methods

Concrete Curing Methods

Protective measures against premature drying are:

·     Applying liquid curing agents

·     Leaving in the forms

·     Covering with sheets

·     Laying water-retaining covers

·     Spraying or “misting” continuously with water, keeping it effectively submerged and

·     A combination of all of these methods

Liquid curing agents can be sprayed onto the concrete surface with simple tools (e.g. low pressure, garden type sprayers). They must be applied over the whole surface as early as possible: on exposed concrete faces immediately when the initial “shiny” surface of the fresh concrete becomes “matt”, and on formed faces immediately after striking. It is always important to form a dense membrane and to apply the correct quantity (in g/m²) as specified, and in accordance with the directions for use. Several applications may be necessary on vertical concrete faces.

Leaving in the form means that absorbent timber formwork must be kept moist and steel formwork must be protected from heating (i.e. by direct sunlight) and from rapid or over-cooling in low temperatures.

Careful covering with impervious plastic sheets is the most usual method for unformed surfaces and after striking of formwork components. The sheets must be laid together overlapping on the damp concrete and fixed at their joints (e.g. by weighing down with boards or stones) to prevent water evaporating from the concrete.