Question 1

What is the difference between air-entrained and regular concrete?

Accepted Answer

Air-entrained concrete has billions of microscopic air bubbles intentionally introduced into the mix; regular (non-air-entrained) concrete does not. Those tiny bubbles — typically 4–7% of the mix volume — are the single most important feature protecting concrete from New Brunswick's relentless freeze-thaw cycles.

Here is the problem that air entrainment solves: concrete is not perfectly solid. It has microscopic pores and capillaries that absorb water. When that water freezes, it expands by abo

Question 2

Why is air-entrained concrete important in New Brunswick?

Accepted Answer

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 a

Question 3

What PSI concrete should I use for a driveway in NB?

Accepted Answer

For a driveway in New Brunswick, specify a minimum 4,000 PSI (approximately 28 MPa) air-entrained mix. Many experienced NB contractors default to 4,500 PSI (32 MPa) for driveways, and for good reason — the higher strength pairs with better durability in our freeze-thaw environment.

In Canadian concrete specifications, strength is typically expressed in megapascals (MPa) rather than PSI. The common equivalents you will hear from NB suppliers and contractors are 20 MPa (2,900 PSI), 25 MPa (3,600

Question 4

Rebar vs wire mesh for a concrete driveway in New Brunswick — which is better?

Accepted Answer

For a residential concrete driveway in New Brunswick, rebar (10M on 18-inch centres) is the better choice — it provides stronger crack control and holds slab sections together more effectively if cracking does occur. Wire mesh is common and far cheaper, but rebar delivers meaningfully better performance for the conditions NB driveways face.

Let's be clear about what reinforcement does in a concrete slab: it does not prevent cracking. Concrete shrinks as it cures and moves with temperature swing

Question 5

What is fibre-reinforced concrete and should I use it in NB?

Accepted Answer

Fibre-reinforced concrete has small fibres — typically synthetic polypropylene or steel — mixed directly into the concrete batch to improve certain performance characteristics. In New Brunswick, fibre reinforcement is a useful upgrade for flatwork, but it is a supplement to — not a replacement for — conventional steel reinforcement.

The most common type used in residential NB concrete is synthetic fibre (polypropylene). The ready-mix plant adds small fibre bundles (typically 12–19 mm long) to t

Question 6

What type of concrete sealer is best for NB driveways?

Accepted Answer

A penetrating silane/siloxane sealer is the best choice for concrete driveways in New Brunswick. It protects the concrete from the inside without changing its appearance, resists the damage from de-icing salt and freeze-thaw cycling, and lasts 2–4 years between reapplications.

New Brunswick driveways face a specific combination of attacks that makes sealer selection important: 150+ annual freeze-thaw cycles, heavy road salt exposure from November through April, and the general moisture load of

Question 7

How much concrete do I need for a 20x20 foot patio slab?

Accepted Answer

A 20×20 foot patio slab at 4 inches thick requires approximately 5 cubic yards of concrete. Here is the full calculation and what it means for your NB project.

The formula is straightforward: Length × Width × Thickness (all in feet), then divide by 27 to convert cubic feet to cubic yards.

20 ft × 20 ft × 0.33 ft (4 inches) = 133.3 cubic feet ÷ 27 = 4.94 cubic yards, rounded to 5 cubic yards.

Always order 5–10% extra to account for ground irregularities, spillage, and the fact that you never w

Question 8

What is the correct slump for concrete in NB flatwork?

Accepted Answer

The correct slump for concrete flatwork in New Brunswick — driveways, patios, sidewalks, and garage floors — is 100–125 mm (4–5 inches). This range provides good workability for placing and finishing while maintaining the low water-to-cement ratio required for durable NB concrete.

Slump is a measure of concrete consistency and workability — how readily it flows and responds to finishing. The slump test is simple: fresh concrete is placed in a cone-shaped mould, the cone is lifted, and the dista

Question 9

Should I use high-early strength concrete for a late fall pour in NB?

Accepted Answer

Yes — for any pour in October or November in New Brunswick, high-early strength concrete (Type HE or 32+ MPa) is strongly recommended. It gains strength faster than standard mixes, reducing the window during which the concrete is vulnerable to freezing — which is the primary risk in late-season NB pours.

Standard concrete (Type GU, General Use) follows a predictable strength gain curve: roughly 70% of 28-day strength by 7 days, 85% by 14 days, 100% by 28 days. In NB fall conditions — cool night

Question 10

What is the difference between 25 MPa and 32 MPa concrete?

Accepted Answer

25 MPa (approximately 3,600 PSI) and 32 MPa (approximately 4,600 PSI) are both standard ready-mix concrete strengths used in New Brunswick, but they serve different applications — and for most exterior concrete in NB, 32 MPa is the correct choice.

The number represents compressive strength: the load the concrete can bear per unit area before it fails, tested at 28 days. 32 MPa can handle 28% more compressive load than 25 MPa. But in NB residential concrete, the strength difference is less impor

Question 11

Can I use bagged concrete mix for a small patio in NB?

Accepted Answer

Bagged concrete mix works for very small projects — sonotube footings, fence posts, repair fills — but is not practical or economical for even a modest patio in New Brunswick. For anything larger than about 20 square feet, ready-mix is the better choice.

The math tells the story. Bagged concrete mix (Quikrete, Bomix, or similar) is sold at NB building supply stores in 30 kg bags for $5–$8 each. One 30 kg bag yields approximately 0.014 cubic metres (0.5 cubic feet) of concrete. A small patio — s

Question 12

What is a concrete admixture and when should I use one in NB?

Accepted Answer

A concrete admixture is a chemical added to the mix — beyond cement, water, and aggregates — to modify the concrete's properties for specific conditions or performance goals. In New Brunswick, admixtures are practical tools for managing cold-weather pours, improving workability, accelerating or retarding set time, and extending durability.

The ready-mix plant adds admixtures during batching, though some (like calcium chloride in small quantities) can be added at the site. Here are the most rele

Question 13

Penetrating sealer vs acrylic sealer for concrete in New Brunswick?

Accepted Answer

For most concrete surfaces in New Brunswick — driveways, sidewalks, exposed patios — a penetrating sealer (silane/siloxane) is the superior choice. Acrylic sealers have their place, but the demanding NB climate makes penetrating protection the better long-term investment for high-exposure surfaces.

The fundamental difference is how each product works. Penetrating sealers absorb into the concrete and chemically react with the calcium silicate compounds in the paste, creating a hydrophobic barrie

Question 14

What type of rebar should be used in NB foundations?

Accepted Answer

For New Brunswick foundation work, standard 15M (metric 5, 5/8-inch diameter) Grade 400 deformed rebar is the most common specification — used for foundation walls, grade beams, and heavily loaded structural elements. 10M (metric 3, 3/8-inch) is used for lighter applications and tie bars. Epoxy-coated rebar is recommended in high-moisture or coastal environments.

Rebar in Canada is classified by bar diameter (10M, 15M, 20M) and yield strength grade (Grade 400 = 400 MPa yield strength is standar

Question 15

How many bags of concrete do I need for a sonotube footing in NB?

Accepted Answer

The number of bags depends on the sonotube diameter and the depth of the footing — but for a typical NB deck post footing, plan on 3–6 bags of 30 kg premixed concrete per tube. Here is how to calculate it precisely for your project.

In New Brunswick, sonotube (cardboard tube) footings for decks, fences, and post structures must extend below the frost line — a minimum of 4 feet (1.2 metres) below grade in southern NB (Moncton, Fredericton, Saint John, Riverview), and 4.5–5 feet (1.4–1.5 metres)

Question 16

What is the water-to-cement ratio and why does it matter?

Accepted Answer

The water-to-cement ratio (w/c ratio) is the weight of water in a concrete mix divided by the weight of cement — and it is the single most important variable controlling concrete strength and durability. For NB exterior concrete, the maximum w/c ratio is 0.45 per CSA standards for freeze-thaw exposed concrete.

Here is the fundamental relationship: the less water relative to cement, the stronger and more durable the concrete. A 0.40 w/c ratio produces denser, stronger concrete than a 0.55 ratio.

Question 17

How many cubic yards of concrete do I need for a standard NB driveway?

Accepted Answer

A standard two-car concrete driveway in New Brunswick — approximately 20 feet wide by 40 feet long (800 square feet) at 5 inches thick — requires roughly 12.3 cubic yards of concrete. A more modest single-car driveway at 10 feet wide by 40 feet long (400 square feet) at the same thickness needs about 6.2 cubic yards.

The calculation is straightforward: length (feet) × width (feet) × thickness (feet) ÷ 27 = cubic yards. For thickness, convert inches to feet: 4 inches = 0.333 feet, 5 inches = 0.4

Question 18

How do I calculate how much concrete I need for my project in NB?

Accepted Answer

The core calculation is simple: (length in feet × width in feet × thickness in feet) ÷ 27 = cubic yards. Divide by 27 because there are 27 cubic feet in one cubic yard, which is how ready-mix concrete is sold in Canada.

Convert your thickness from inches to feet before calculating: 4 inches = 0.333 feet, 5 inches = 0.417 feet, 6 inches = 0.500 feet. So a 20 × 30 foot patio at 4 inches thick is: 20 × 30 × 0.333 ÷ 27 = 7.4 cubic yards.

For irregular shapes, break the area into rectangles, triang

Materials & Concrete Mixes