Can You Pour Concrete Over Crushed Concrete?


Are you tired of seeing crushed concrete on your driveway and are wondering if you can pour concrete over it? Your driveway plays a huge part in your home. Aside from being an investment, it also affects how the exterior of your house will look. Concrete is a popular choice for driveways, but can you pour it over crushed concrete? Check out the answer below.

Can you pour concrete over crushed concrete? You can pour concrete over crushed concrete. Pouring concrete directly into the ground makes it vulnerable to erosion that can cause cracks and other damages. Aside from that, the tiny plants or roots under the concrete slab can lead to unevenness. To prevent such issues, you can use crushed concrete as your base before pouring the concrete.

What are the advantages of crushed concrete as a road base? Is crushed concrete a good base? Can you pour new concrete over cracked concrete? Why is a concrete slab base necessary? These are some of the questions that we will discuss. Read the rest of the article below for more tips and information.

Can you pour concrete over crushed concrete
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Is Crushed Concrete a Good Base?

Crushed concrete makes a good base for driveways. This material locks up well and provides superior load transfer when used over weaker subgrade. Crushed concrete can provide a base for your driveway that is durable and can last for a long time.

The Advantages of Crushed Concrete as a Road Base

The advantage of crushed concrete as a road base is that it has a low compact unit weight, and is environmental-friendly. Crushed concrete can be used as part of a road base and as a coarse aggregate. Let us find out more about these advantages below.

Low Compact Unit Weight

One advantage that you can get from crushed concrete is that it has a low compact unit weight as compared to other base materials like aggregates. Hence, crushed concrete has a greater volume for the same weight which makes it an affordable and durable option for your driveway.

Environmental Benefits

Crushed concrete also has its environmental benefits. Recycling concrete to be used in other projects means that fewer raw materials are wasted and that the existing concrete is not left to sit on the landfill for a long time.

Can You Pour New Concrete Over Old Concrete?

New concrete can be poured over old concrete as long as it is done properly. About two inches thick of new concrete should be poured. Aside from that, it is recommended to use smaller aggregate and to use reinforcement like fiber into the concrete. If the slab is so thick that it makes it hard to use fiber, you can opt for steel rebar.

When is it Not Okay to Pour Concrete Over Old Concrete?

It is not okay to pour concrete over old concrete if there are large cracks in the old slab. Moreover, if there are tree roots that make the concrete heave, it is ideal to tear it down so that you can also get rid of the roots and other possible damages that the concrete has. Pouring new concrete over damaged concrete can cause problems in the future. This also means that the new concrete is not as durable as it should be because the base is already damaged.

Why is a Concrete Slab Base Necessary?

A concrete slab base is necessary because it promoted drainage and reduces settlement. Daily traffic and different condition can take a toll on your driveway. If the concrete slab does not have the right base to support it, it can easily get damaged. Let us learn more about this below.

Reduces Settlement

Concrete slab base reduces settlement. Take note that the dirt underneath the concrete slab moves constantly. The base provides a layer that absorbs any movement that might occur in the soil which effectively prevents cracking in the concrete slab

Promotes Drainage

A concrete slab also prevents drainage if it is poured on dirt. The dirt will eventually be washed away and the concrete slab will start to crack and sink. Gravel can be used as a base to support it and to prevent cracking. You can also check out this article that we have shared titled, what is the most durable material for a driveway? We have shared helpful tips and information that you can refer to.

How to Pour Concrete

To pour concrete, there are a few things that you need to do which include preparing the area, forming, mixing, placement, finishing, troweling, and curing. Below is the step-by-step process of how to pour concrete on your driveway.

#1. Prepare the Area

The first thing that you need to do is to prepare the area. This will lessen the chance of heaving that can be caused by frost and soil expansion. If you are working on a small area in your driveway, you can use hand tools to clear the surroundings and expose the dirt beneath. On the other hand, you need to use earth-moving equipment if you are working in a large area. Once you clear the area, pour a sub-base of gravel into it.

#2. Forming

The next thing that you need to do is to set the forms. When working on a residential driveway, you can use wood forms with wood stakes or metal. Using screws, attach the forms to the stakes. Make sure that the forms are in good condition. Next, provide the right slope for the drainage.

#3. Mixing

You can use bagged concrete that can be purchased at your local hardware store. Properly mix the concrete with water. Follow the instruction written on the directions written on the packaging. A wheelbarrow and shovel can be used for working with small slabs. On the other hand, you need to have a concrete mixer if you are working on a wider area.

#4. Placement

Once you have properly mixed the concrete and have the right equipment to pour it, you can start the next step which is placement. Carefully pour the wet concrete into the forms making sure that they are full to the top edge. Use a shovel to move the concrete while it is being poured so that there will be no air pockets.

#5. Early Finishing

Level the top of the concrete using a wood board or a large metal. This will help make the concrete more compact. Make sure that it is smooth and level. You also need to use a float to make that the concrete is compact. Use hand-held floats for the edges. If you are working on large areas, use larger bull floats.

#6. Troweling

There is no need for additional finishing if the concrete will have a rough broom finish. However, if the concrete will be stamped, you need to do a steel trowel finish. Allow the concrete to sit until its surface starts to firm. If it is firmed, create a smooth and uniform finish with the use of a steel trowel

#7. Final Finishing

The next step is to do the final finishing. The common type of finish is the broom finish. To do this, a special type of broom is pulled across the surface of the concrete. This creates a rough and textured surface. You can also choose other types of finishes according to your preferences.

#8. Curing

The last step is curing. Allow the concrete to rest so that it starts to cure. The curing process will take about 28 days. To help the concrete cure slowly and evenly, apply curing and sealing compound. This reduces curling, surface discoloration, and crack on the concrete as it sets.

✅ Video – How to pour a Concrete Driveway Addition for Beginners DIY

Odell Complete Concrete shared the video below on YouTube. The video shows how to pour concrete driveway for beginners. In the video, the steps and process on how to pour a concrete is shown. Check out the video below for more tips and information.

What Material is Used for a Slab Base?

Crushed stones are the common materials used for a slab base. Contractors usually use a mix of coarse and fine aggregate for the base. These materials create a compact base that is also safe for drainage. We have also shared this article that discusses what the cheapest material for a driveway is. You can check out the article for an in-depth discussion about the topic.

How Thick Should Concrete Overlay Be?

The minimum thickness of a concrete overlay that is recommended should be about one to two inches. This should be done for fully bonded concrete overlays that are placed on a base slab. The slabs should also be from cracks and of good quality.

Does Concrete Stick to Old Concrete?

Concrete does not stick to old concrete. The reason for this is that the cement in a concrete mix does not have natural bonding agents. Hence, when you add fresh concrete over existing concrete, they will not stick together. To remedy this problem, you can use a bonding adhesive.

Conclusion

You have reached the end of this article that discusses if you can pour concrete over crushed concrete. We have learned that you can pour concrete over crushed concrete as long as it is in good condition. Crushed concrete can be used as a sub-base over new concrete and it has many benefits. We have also shared tips on how to pour concrete on your driveway. We hope that this article has helped you learn more about crushed concrete and its benefits. Thank you for reading!

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