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How to Pour a Concrete Slab on Asphalt Driveway

Asphalt, also known as blacktop, is a useful driveway material. However, it is more expensive and less durable than concrete. It is prone to cracking, which can lead to expensive repairs. Replace your asphalt driveways with concrete for a cheaper and longer lasting driveway that will thrive in areas prone to regular freezing and refreezing that causes cracks and deterioration in asphalt.

Things You'll Need

  • Sledgehammer, kangoo hammer or digger
  • Shovel
  • Tamper
  • 2"-by-6" wood
  • 1"-by-2" wood
  • #3 rebar grid
  • 2-inch concrete dobies
  • 3,000 PSI concrete mix
  • Bull float
  • Concrete curing compound
  • Slim spade or trowel
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    • 1

      Break up the asphalt. For larger sections, use a digger or a kangoo hammer. For smaller sections, use a sledgehammer. Pieces should be no more than one inch wide. Spread the broken asphalt evenly over the surface of the driveway using shovels. Tamp down using a mechanical tamper.

    • 2

      Frame the edge of the driveway with 2"-by-6" pieces of timber. This frame acts as a mold that provides a defined edge to your concrete driveway. Insert lengths of 1"-by-2" wood every 12 feet of driveway to act as an expansion joint, which prevents cracking.

    • 3

      Place a #3 rebar grid supported by two-inch concrete dobies so that it lies in the center of the driveway and forms a continuous grid. This acts as reinforcement to the driveway.

    • 4

      Order 3,000 PSI concrete from a concrete delivery firm. The number refers to the amount of weight the concrete will bear. The US Department of Agriculture recommends 3,000 PSI concrete for driveways.

    • 5

      Pour the concrete in the center of the mold. Move it to the corner with shovels. Pour in sections as necessary. Level the concrete using a bull float, which resembles a plank of wood or metal with a long handle. Spray a concrete curing compound onto the wet concrete. Allow to dry for 24 hours.

    • 6

      Separate the 2"-by-6" timber from the outside of the driveway using a trowel or a slim spade. The 1"-by-2" wood remains in the driveway. Backfill the holes left by the timber with soil or crushed rock. Allow to dry for a further five days before using.