BILD Calgary Region

Bulletin – October 6th

Tom Strangward, Senior Coordinator, Technical & Standing Committees

Hot Mix Asphalt and Cement Concrete – Cold Weather Requirements

As per City of Calgary Roads Specs, cold weather/off season requirements started for all asphalt and concrete works after September 30th.

As reminders, some of the common off-season requirements for Concrete as per City Specs are:

  • The minimum allowable concrete compressive strength shall be attained in seven days.
  • When concrete is placed in cold weather, all equipment needed for adequate protection and curing shall be on hand and ready for use before concrete placement is started
  • Snow and ice shall be removed using heat where necessary. In no case shall concrete be deposited on or against any surface that is at a temperature of less than 5°C.
  • If the Contractor uses forced air heating units, the concrete shall be kept continuously moist during the complete heating and curing period. Combustion type heaters may be used but they shall be so constructed and so placed that their combustion gases do not come in contact with surfaces of the concrete during placing and curing causing carbonation of concrete.

For all other details of Concrete Winter Off season requirements, please refer to Sec 311.01.06 – Cold Weather Requirements and Sec 311.06.02 – Placing of Concrete.

Similarly for Asphalt, Hot Mix Asphalt Placing Temperature, the requirements are:

  • No hot mix asphalt shall be dispatched to the field unless the temperature, as issued by Environment Canada, is rising and meets the following minimum temperature requirements:
    • Lift Thickness less than 50 mm, 7°C.
    • Lift Thickness greater than 50 mm and less than 70mm, 4°C.
    • Lift Thickness greater than 70 mm, 2°C.
  • A tolerance will be permitted for plant start-up.
  • No surface lift asphalt mix shall be placed regardless of temperature or thickness until the road surface is 5°C or higher

For all other details of asphalt off season requirements, please refer to the relevant sections of Sec 307.00.00.

For Pavement Design – Pages 164, 167, 168  are related to Pavement structures in Cold weather ( Optional, applicable for construction after Sep 30 ). This shall be not translated to allow any paving when there is snow or temperatures is below freezing.

For further information and questions or comments, please contact Nasir-ul Mulk at Nasir-ul.Mulk@calgary.ca.