How Are Concrete Sleepers Reinforced?

Concrete sleepers aren’t made from concrete alone. Though concrete is a strong building material, it needs some reinforcement to provide the support needed for that retaining wall on your property.

In this post, we’ll look at how concrete sleepers are reinforced, but before we do, let’s look at the role concrete sleepers play, and why it’s so important they are super strong.

The advantages of concrete sleepers

Concrete sleepers have a number of advantages for use as retaining walls.

  • They’re built to last. Unlike timber sleepers, concrete sleepers won’t become infested by pests or decay, and if properly looked after, can last a lifetime.
  • They can be built higher. Because of the strength of the reinforced concrete sleeper, retaining walls can be much higher than those built with many other materials. (Concrete Sleepers Melbourne sells sleepers that can be built to 4.5 metre heights). Note that appropriate council approval is needed for retaining walls higher than one metre. See our post: How high can concrete sleeper retaining walls go?
  • They come in a variety of surfaces, meaning that if you love the natural look of timber or stone, you can buy concrete sleepers cast to appear like those materials.
    You can get charcoal or pine-coloured (jasper) wood grain concrete sleepers for a timber look. Stackstone concrete sleepers for a rocky finish, or smooth concrete sleepers in plain or charcoal for a more industrial look.
    Concrete sleepers can also be manufactured in a sandstone tone if requested
    See our post: Types of concrete sleepers.
  • They are reinforced with steel, so they are super strong to comply with the engineering requirements and relevant standards
  • They provide adequate support as retaining walls provided that accommodation is made for appropriate water drainage to prevent wall failure. (This could be piped drainage that disposes of water away from behind the wall to reduce pressure build up, or the use of free-draining sand.)
  • They are cost-effective and easy to source.
  • They are easy to install, due to their being precast, and coming with steel posts that slot easily into place. See our post: How to build a sleeper retaining wall with steel posts.
  • They can be used as steps in your landscaped garden, so that you can ensure your steps match the rest of your retaining wall. This keeps a streamlined look.

How are concrete sleepers reinforced?

There are two parts to the reinforcement of your concrete sleepers. The first part is in the sleepers themselves. Unlike poured concrete, concrete sleepers are reinforced with steel, usually N-12, N-16 or N10 bars. These bars are manufactured with surface deformations to create locking anchorage with surrounding concrete.

Each concrete sleeper sold at Concrete Sleepers Melbourne contains two N-12 bars unless is specified or has been engineered to be replaced for a similar option.

In addition to the N-12 reinforcement within the sleeper, the sleeper is further strengthened by steel sleeper posts that are used to support it. These galvanised steel posts come in different lengths, and are shaped according to what part of the sleeper they need to support (middle panels, end panels, corner panels etc.).

All of our concrete sleepers are engineer-certified (engineering certificates are available on our website.)

Proper installation

It goes without saying that no matter how strong the concrete sleeper, your retaining wall needs to be correctly constructed. For small jobs, you may be able to proceed yourself, but for walls higher than 1 metre, ensure you seek correct council approval before you start. You may need an engineer to look at your property, particularly if you live somewhere prone to landslides or slips.

Why do we need concrete sleepers?

When it comes to landscaping on your property, building decent retaining walls is usually the first step. Once retaining walls are correctly erected, your outdoor areas are safe for your family and neighbours, and you can proceed to plant out garden beds and trees, set up your outdoor leisure areas, and maybe put in a pool (if you’re lucky).

Retaining walls aren’t needed in every backyard, but are sometimes necessary for the following reasons.

  • A retaining wall is needed when there are changes of height on your property. To hold back banks of earth, you basically need a wall to do it. Without it, the earth can simply erode and crumble, which poses obvious dangers.
  • Retaining walls on sloped land allow you to create different zones on your property. These zones can be used for different purposes, both practical and aesthetic. All you need is some concrete sleeper steps between zones, and you can have your separate veggie patch, kid’s play area, driveway, and so on. In one zone, you could plant native plants, and in another zone, an English cottage garden. You can even bring in earth to deliberately create different levels, or alternatively, carve out earth to achieve this.
  • Retaining walls can help to minimise erosion. Even if you didn’t start out with a retaining wall, you might notice an area on your land that is eroding and could do with some support. Retaining walls are a simple tool to help keep land in place, and when installed correctly, they can assist with preventing small slips of land.

Why use concrete sleepers for retaining walls?

There are a number of materials that can be used to build retaining walls. These include steel, stone, timber sleepers, bricks. There are pros and cons for each.

  • Bricks: Bricks are strong and durable, but labour intensive. Brick retainers also require special drainage systems.
  • Wood: Timber is fairly easy to install, and blends well into the landscape, however it is only suitable for low retaining walls, and will need to be replaced eventually. Untreated wood is prone to rot and termite damage, and treated wood (which lasts longer) may be toxic for your garden, as most timber is treated with arsenic. There are less toxic treated woods out there—treated with ACQ or Alkaline Copper Quaternary, which is less dangerous to your garden, kids and pets—but these may be more costly.
  • Stone: Stone is a lovely product for a retaining wall, but it can be difficult to source stone and you need a stonemason to erect a quality wall. It can also be difficult to control water flow with stone.
  • Steel: Steel retaining walls can look great, especially if you’re comfortable with their colour changes. Steel is expensive, however, so it will be few people’s first choice.

To summarise…

Concrete sleepers are a great option for building retaining walls. They look great, are durable, and importantly, are reinforced with steel bars to ensure superior strength.

Concrete Sleepers Melbourne can provide you with a variety of concrete sleepers and sleeper posts in different colours and textures. Contact us for more information today.