4 ways to make exposed aggregate concrete

4 ways to make exposed aggregate concrete

Are you considering installing new concrete surfaces but are unsure which exposed aggregate concrete would best fit your project? Alternatively, are you curious about exposed aggregate concrete and want to learn more about it?

If so, I am here to help. I have collected information on four of the most common techniques for creating exposed aggregate surfaces on concrete. By comparing these techniques, you can decide the best fit for your needs and working style.

Exposed aggregate concrete is a great way to add a unique and special touch to your project. You can use four techniques to create this finish: seeded, polished, washed, and exposed. Each method suits specific instances well and produces beautifully told aggregate finished products.

When deciding which technique to use, you should consider whether the concrete is old and cured ages ago or if it is still being made. I will provide two examples for each scenario to help you choose the best technique for your project.

By reading on, you will understand how to install exposed aggregate concrete in four different ways.

Brushing and washing

The brushing and washing technique is the simplest way to get the aggregate in concrete to show. It is best used in smaller applications instead of large projects. It can be done without any dangerous chemicals or special tools.

Essentially, this technique of exposing the aggregate stones in your concrete is only spraying or sweeping the cement paste off from the aggregate under the paste. Use a stiff broom or a steady stream of pressurized water to gently remove the cement paste without harming the aggregate.

This is for more minor projects because concrete areas curing with water are usually a bad idea. It will mix the water/cement ratio on the concrete, resulting in not-so-optimal strength. This is why I prefer the following method over this.

Also, this technique must be used correctly (i.e., when the cement paste is still soft but the aggregate is solidified and will not get dislodged from the strain), so it can be challenging for beginners. I want to experience this before doing a whole driveway; a few self-made concrete pads could be a good start.

Surface retarder

Another way you can achieve the goal is by using an exposed aggregate concrete retarder on the surface of the concrete. This chemical is designed to keep the cement paste from setting so fast, giving workers a longer period to scrub off the cement paste to expose the aggregate rocks.

This spray is applied directly after the concrete has been laid, allowing the concrete layers to hold off on the exposing process for about twenty-four hours. Using this chemical allows larger jobs to be done over a much extended period than would usually be permitted without the retardant.

For this reason, it’s much better for beginners. Well, I’ve worked with concrete for years and’d use it as well. The extra time for curing concrete is always a blessing when we don’t want it to get hard too fast. It will help everyone get better results. I’d recommend going with this if you’re considering exposed aggregates.

Sandblasting/washing

The last method of creating exposed aggregate concrete is to use a sandblaster to erode the cement paste away from the rock. The good side of this method of doing it like this is that it can be applied to old concrete. By old, I mean on concrete that was laid years ago.

However, the major disadvantage of this method is that the blasting process can chip and wear down the aggregate rock, sometimes even fracturing the individual pebbles.

Also, if you do it with dry sand, you will need protective gear for your eyes and lungs. With water, it’s good to have protection, as well as the sand and loose concrete, which can cause actual harm as they’re blasting at high pressure.

This leads to a bit more worn appearance, and the aggregate could be more shiny using one of the other methods. If you are looking for the best method to preserve the color and beauty of the individual pebbles, this method should be avoided.

Acid washing

I put the acid washing to the last spot as it is more complicated than sandblasting/washing old concrete. There are also more limitations as it is harder to do walls than floors, and the workers need more protection.

In a way, it is a gentler way to expose the aggregates than working with sand. Still, on the other hand, it is harder to control where it goes, like with the exposed aggregate concrete wall case.

Most of the time, the process is watering the concrete or applying the acid with spray or another method. Then, it would help if you waited for some time, depending on how strong the acid is. Then it’s washed and neutralized and washed a few times more.

The process is repeated to get the results you want. It can also damage the concrete, so it should be carefully done.

Conclusion

Transforming your concrete floor, patio, or walkway with a “pebbled” look can be achieved using any of the four primary techniques available. Each technique has its unique texture, and the choice of method ultimately depends on your preferences while working with concrete.

While the brush and spray method is the easiest, it is also the quickest, offering the worker the least time. You could use a surface retardant to slow down the concrete’s setting process to achieve the desired result.

If your concrete is old and needs a fresh face, the blasting method may be the best option, considering that working with acid can be challenging. All four methods have proven to produce good results, and they can transform your dull concrete floor into a beautiful and natural piece of art.

However, taking steps to protect the surrounding environment when using any of these methods is crucial. Acid washing can harm vegetation, sandblasting can produce a lot of sand and concrete dust, and washing fresh concrete may create dirt. So, make sure to take all necessary precautions.