In 2012, after negotiations with multiple stakeholders, the revised City of Calgary (The
City) Standard Specifications for Roads Construction were implemented. The summer
construction season in Calgary is short and winter conditions can occur as early as
September. The specifications for Concrete Sidewalk, Curb and Gutter define cold
weather air temperature and the curing requirements for the off-season concrete in
accordance with CSA A23.1. The Urban Development Institute of Calgary proposed lower
temperature limits for winter construction combined with limited concrete protection to
extend the construction season for concrete works. However, The City is reluctant to relax
the winter concreting and curing regime as the value of the backlog of concrete sidewalk
repairs and replacement is high, and increasing, with many failures attributed to offseason
concrete construction practices.
The City commissioned Tetra Tech EBA Inc. (EBA) to undertake a comprehensive review
of sidewalk construction specifications and the requirements for winter curing by other
municipalities across Canada, and, to develop a cold weather placing and testing
protocol. The guidelines for concrete placement, the testing protocol for laboratory and
field testing, and the acceptance criteria were developed. In October and November of
2013, a comprehensive research program was conducted and the results were compiled
in consideration for relaxing the existing specifications for concrete sidewalk construction.
This paper describes in detail the process and the data analysis. The technical aspects
and the impact of the potential changes to the winter curing construction practices on
the sustainable quality concrete surface works are discussed.
