What is exposed aggregate concrete and is it good for NB driveways?

Exposed aggregate concrete is a decorative finish technique where the smooth cement paste surface is washed away to reveal the natural stone aggregate underneath — and yes, it is an excellent choice for New Brunswick driveways, offering durability, traction, and visual appeal that holds up well through NB winters.

The process is straightforward: concrete is poured and levelled normally, then a chemical surface retarder is applied (or the surface is water-washed) to expose the top 3-6 mm of aggregate before the cement paste fully hardens. The result is a textured surface with natural pebble or stone aggregate embedded throughout — the final appearance depends on the aggregate selected. Standard ready-mix aggregate produces a mixed grey-and-brown stone look. Premium exposed aggregate finishes use washed river stone, coloured quartz, or decorative pebbles mixed into the concrete for more vibrant colour and texture. In NB, river stone aggregates in warm browns and greys are a popular, natural-looking choice.

Why it works well for NB driveways. The textured aggregate surface provides inherently better traction than a smooth broom finish — a meaningful safety benefit in NB winters when driveways are subject to ice and packed snow from November through March. The texture also hides minor surface wear and salt damage that would be visible on a smoother finish, so exposed aggregate driveways tend to look good longer with less maintenance than stamped concrete. The aggregate surface has no film to peel or chip (unlike stamped sealers or epoxy coatings), which is an advantage in NB's freeze-thaw environment.

Specification requirements are the same as any NB driveway. Air-entrained concrete (25-32 MPa, 4-7% air content) is essential. Driveway thickness should be 5-6 inches with rebar or welded wire mesh reinforcement. A compacted 6-inch granular base is required. Control joints should be saw-cut or tooled at 10-12 foot intervals. The same freeze-thaw durability rules that apply to broom-finish concrete apply to exposed aggregate.

Sealing is still recommended. While exposed aggregate is more durable than stamped concrete without sealing, a penetrating silane-siloxane sealer applied every 2-3 years protects the aggregate-paste bond from salt intrusion and freeze-thaw damage. This is especially important in the first 1-2 years after placement when the surface is most vulnerable. An acrylic sealer gives exposed aggregate a wet, enhanced colour look — some homeowners love it, others prefer the natural matte appearance.

Cost in NB. Exposed aggregate driveways run $10-$16 per square foot fully installed — more than plain broom finish ($8-$15) but less than stamped concrete ($12-$20). The premium reflects the additional labour of the surface wash/retarder process and any decorative aggregate upgrades. A typical two-car driveway (400-500 sq ft) runs $4,000-$8,000. New Brunswick Concrete can match you with local contractors who specialize in exposed aggregate finishes for a free quote.