Best Practice - Cold Weather Exposed Concrete
Subgrade & Formwork
All snow and ice shall be removed before concrete is placed on any surface. In order to pour, the surface must be at a minimum of 5 degrees Celsius, and after placing the concrete it must be protected and maintained at a temperature not less than 10 degrees Celcius for 3 days. Calcium chloride or other de-icing salts shall not be used as de-icing agents in the forms.
Settlement conditions for a slab on grade is generally caused as a result of unsuitable sub-grade. Proper compaction or clean coarse aggregate should be considered.
Placing of Concrete in Cold Weather
When the air temperature is below 5 degrees Celsius, concrete shall be kept at a temperature of not less than 10 celsius for a minimum of 72 hours (3 days) after placing. Concrete should be protected by means of heated enclosures, insulated covering blankets or other suitable means. Form work should be kept in place for a minimum period of 7 days.
Finishing Methods for Concrete Slabs
Suggested broom finish for porches and garage floor slabs instead of smooth trowelling.