Why is air-entrained concrete important in New Brunswick?

Air-entrained concrete is not optional in New Brunswick — it is the minimum specification for any concrete that will be exposed to weather. NB experiences approximately 150 freeze-thaw cycles per year, one of the highest rates in Canada, and non-air-entrained concrete simply does not survive this climate.

New Brunswick's Maritime location creates a uniquely punishing concrete environment. Temperatures fluctuate above and below freezing repeatedly throughout the winter, particularly in coastal areas and river valleys. It is not just the cold that damages concrete — it is the cycling. Every time water absorbed into the concrete's pore structure freezes, it expands by 9%, building hydraulic pressure within the concrete matrix. Every time it thaws, that pressure releases and new water is drawn in for the next cycle. Repeat 150 times a year and the internal cracking is cumulative and irreversible.

Salt makes it dramatically worse. NB roads are heavily treated with sodium chloride from November through April, and that salt-laden slush and spray reaches every driveway apron, front walkway, and patio near a road. De-icing salt lowers the freezing point of water, creating additional freeze-thaw cycles at the concrete surface at temperatures where the concrete itself would normally be safe. Salt also concentrates at the concrete surface as water evaporates, drawing moisture back into the pores repeatedly.

Air entrainment addresses this by distributing billions of microscopic air voids (typically 0.004–0.008 inches in diameter) throughout the concrete. These voids act as pressure relief valves — when freezing water expands in the capillaries, it migrates into the adjacent air void rather than fracturing the concrete matrix. The spacing factor (the average distance from any point in the paste to the nearest air void) is critical: properly air-entrained concrete has voids spaced every 0.008 inches or less.

The cost comparison is obvious: air-entrained ready-mix costs approximately $10–$20 more per cubic yard than standard mix in NB. A typical two-car driveway uses 7–9 cubic yards, so the premium is $70–$180 on a $6,000–$8,000 project. Non-air-entrained concrete on the same driveway will likely need to be replaced within 5–7 years as spalling and scaling destroy the surface. Air-entrained concrete, properly placed and sealed, will last 25–40 years.

When you receive quotes from concrete contractors in Moncton, Fredericton, Saint John, or anywhere else in New Brunswick, ask explicitly whether the mix includes air entrainment. Any contractor not specifying air-entrained mix for exterior flatwork is a red flag. New Brunswick Concrete can help you find contractors who specify the right materials from the start.