Title:
Concrete Q & A: Cold Weather Effects
Author(s):
Ward Malisch
Publication:
Concrete International
Volume:
32
Issue:
4
Appears on pages(s):
80
Keywords:
DOI:
Date:
4/1/2010
Abstract:
We’ve completed concrete placement for a 14 in. (360 mm) thick retaining wall. Our concrete mixture contains 517 lb of Type I cement per cubic yard (308 kg/m3), has a specified water-cement ratio of 0.45, and an air content of about 6%.
The weather has been cold, but we adhered to cold weather concreting requirements in Table 3.2.1 in ACI 306.1.1 The concrete temperature was over 50°F (10°C) during placement, and we used a heated and properly vented enclosure to maintain the formwork and concrete surface temperatures at about 50°F for 3 days. The day after we removed the enclosure, the ambient temperature dropped to about 20°F (–7°C) for a week, but the concrete surface temperature never went below 25°F (–4°C).
The temperature is now above freezing, and we think the concrete has achieved approximately 30% of its 28-day design strength. Are we safe to assume that the concrete won’t be harmed with continued cold temperatures?