Which concrete to use for sidewalk?

When constructing a sidewalk, the choice of concrete is crucial for ensuring durability, strength, and resistance to environmental conditions. Here are the key considerations for selecting the appropriate type of concrete for a sidewalk:

Plain Concrete Sidewalk in Stevens Point
  1. Recommended Concrete Mix


  • Mix Design: Use a 3500 to 4000 psi compressive strength mix. A 4000 psi mix is preferred for areas with heavy pedestrian traffic or exposure to freeze-thaw cycles.
  • Water-Cement Ratio: A lower water-cement ratio (e.g., 0.45-0.50) is ideal for improved durability and reduced permeability.
  • Aggregate Size: Use a mix with coarse aggregates (usually ¾-inch gravel) for strength and smoother finishes.


    2.  Type of Cement


  • Portland Cement Type I or II: These are the most commonly used for sidewalks. Type II is slightly more resistant to sulfate attack, making it suitable for environments with sulfate-rich soils.
  • Air-Entrained Concrete: If the sidewalk is in a region with freezing and thawing conditions, air-entrained concrete is recommended. This type includes tiny air bubbles that allow water to expand without causing damage during freezing.


    3.  Additives


  • Fibers: Polypropylene or steel fibers can be added for additional crack resistance.
  • Admixtures:

                  -  Plasticizers for workability.

                  - Accelerators for faster curing in cold weather.

                  - Retarders for hot climates to prevent cracking.

  • Color Additives: For aesthetic purposes, you can mix pigments into the concrete.


      4. Thickness and Base Preparation


  • Concrete Thickness: Ensure the sidewalk is at least 4 inches thick for standard use. For driveways or areas with occasional vehicular traffic, increase to 5-6 inches.
  • Subbase: Place the concrete over a well-compacted subbase, typically 2-4 inches of compacted gravel or crushed stone, to provide stability and drainage.


  5. Joint Placement

  • Add control joints every 4-6 feet to minimize cracking. Expansion joints should be used at intersections with other structures or at significant length changes.


  6. Finishing and Curing

  • Finishing: Use a broom finish for better slip resistance.
  • Curing: Properly cure the concrete for at least 7 days to achieve strength and prevent premature cracking.


       By following these guidelines and consulting with local building codes, you can ensure a durable and long-lasting sidewalk.