How do I know that my Concrete will last?

Concrete is an extremely durable and long lasting material when installed and maintained correctly. The average life of a concrete driveway in Minnesota is 20-50 years (IDC), although some people have concrete fail earlier, and the average cost to replace is $4,900 (Forbes).

The difference between a driveway lasting two, twenty, and fifty years is in the preparation and ongoing care for the concrete. The important items to ensure your concrete driveway has are: Base Material, Reinforcement, and Surface Cure.

Base Material

The first step after removing the old concrete is to inspect the subgrade. A properly installed concrete driveway will have several inches of a quality compacted gravel base. When concrete is not poured on the proper material, it will suffer from poor drainage, washout, and settling.

Poor drainage can lead to excessive heaving during freeze and thaw cycles. Trapped moisture expands and contracts under the concrete, causing pressure to build under sections of the concrete, making it prone to cracking and fractures.

Washout is due to improper water mitigation and improper material use. Rain or flowing water that runs near or under a concrete slab can lead to erosion, called washout, that can create voids underneath the concrete increasing the tensile load*.

Settling is the sinking of base material over time which can lead to gaps under the concrete, fractures, or the entire slab sinking from its original position. Settling is, unfortunately, unavoidable, but it can be mitigated by using the proper base material and compacting the base before pouring.

Reinforcement

The second step to ensuring your concrete will last is reinforcement. Although care is taken into preparing the base, over time there will be further settling, roots, or drainage issues that increase the tensile load on the concrete. Concrete is used because of its incredible compressive strength* however, it is not exceptionally resistant to tensile loads. The main ways to increase tensile strength are: rebar, wire mesh, and fiber.

Rebar is long pieces of shear resistant material that can be made of steel or fiberglass. The rebar is placed in a grid like structure and tied together before concrete is placed. Rebar is exceptionally good at increasing a slabs resistance to tensile loads that can cause cracking or separation.

Wire mesh are sheets of wire that create small squares, similar to a fence. This is positioned before concrete is poured, and is used to reduce separation, similar to rebar. Mesh is used as a more cost efficient, and smaller footprint alternative to rebar.

Fiber, fiber mesh, and fiberglass mesh refer to small strands of fiberglass (typically under 1″ in length) that are mixed into the concrete before it is placed. Fiber is also used to reduce cracking, but offers more resistance to hairline fractures than separation.

Curing and Sealing

The third, and final step to a long lasting concrete surface is curing and sealing the surface. Concrete can suffer from an issue called delamination. Delamination occurs when the surcface layer of concrete begins to flake off, increasing wear and aging of the slab. The main ways to combat delamination are by slowing the curing process on the slabs surface, sealing the concrete after pouring, and unfortunately, not using salt. Concrete should be re-sealed every 3-5 years for the maximum life of the reinforcement and the surface finish.

Communicate with your contractor

Choosing a reliable contractor can be an exhausting and risky endeavor, one way to help educate yourself when searching is to communicate with them. Ask them:

1. What kind of base material will they be using?
2. How deep will that base be?
3. How will they mitigate water issues?
4. What kind of reinforcement will they use?
5. Will they use a curing compound after the concrete is finished?
6. Do they offer sealing services after the concrete is installed?

If they are not willing to answer one of these questions, or state that the base/reinforcement/cure is not necessary, ask them why, and consider finding a new contractor.

Roxs Concrete LLC

Thank you for reading to the end of this article, if you are looking for a quote on your concrete project, consider reaching out using the button below.

• *Tensile load refers to the load that a material experiences during bending or stretching. In the context of concrete, think of a weight applied in the middle of a bridge.
• *Compressive strength is a materials ability to resist deformation due to

Sources:

IDC https://www.idc-automatic.com/concrete-vs-asphalt-driveway/#:~:text=Concrete%20offers%20property%20owners%20long,years%20to%20its%20life%20span.

Forbes https://www.forbes.com/home-improvement/driveway/concrete-driveway-cost/