Reinforcing concrete sidewalks with wire mesh helps to bridge over small imperfections in the subgrade. This lessens the likelihood that sinkholes will develop. Concrete sidewalks can be replaced in sections that mesh together nicely, although the color does not always match (few materials do). The design life of concrete is approximately 30 years. This means that over a 30-year period, the entire sidewalk system in a given property will need to be removed and replaced. Usually it will be done in sections over time.
- Lay out and mark the areas to be removed and replaced. It is recommended that concrete sidewalk be taken out to the nearest joint.
- Set up warning barriers to make the work site safe.
- Saw cut the perimeter of the repair area to produce smooth, even edges.
- Excavate the deteriorated concrete and haul to a recycling facility.
- If the subgrade material is soft or in poor condition, remove it to a minimum depth of 4″ and replace with crushed stone. Stone should be leveled and compacted thoroughly using a vibratory tamper.
- Install 6 x 6 #10 welded wire mesh.
- Set concrete forms using metal or wood forms pinned at sufficient intervals to keep the forms from disfiguring or “blowing out” when the concrete is introduced.
- Pour sidewalk using 3000 psi or 3500 psi air-entrained concrete. Air entrainment is for exterior concrete only and helps the concrete endure changing weather conditions. Concrete should be a minimum of 4″ thick.
- Trowel the concrete level and score joints in a pattern that keeps the repair area uniform with the surrounding sidewalk. Expansion joints should be placed approximately every 25′.
- Apply broom finish perpendicular to the direction of traffic.
- Once concrete has set, strip forms and remove from the site. Any available dirt from on site can be used to fill the voids where the forms were.
- Remove any remaining trash or debris.