Cutting aggregate concrete - an introduction

Washed concrete is a versatile and robust material that is used in many construction projects.

Difficulty level | Simple costs for 5m²: approx. 50-100 euros | Workload for 5m²: approx. 3 hours

We show you:

• Types of aggregate concrete
• tools and machines
• Instructions for cutting aggregate concrete
• Tips & Tricks

1. What is aggregate concrete?

Exposed concrete is a special type of concrete in which the surface is washed after the concrete has been poured to reveal the underlying aggregate (such as pebbles).

The result is an attractive, non-slip and weather-resistant surface that is used in a variety of applications such as walkways, patios and driveways.

1.1 Types of aggregate elements

These are the most common exposed aggregate concrete elements that need to be cut:

• washed concrete slabs
  
  
• aggregate concrete blocks
  
  
• aggregate walls

2. Why cut aggregate concrete?

Cutting exposed aggregate concrete may be necessary for a variety of reasons. The two most common are :

• Adaptation to individual needs:
  
  If you are using aggregate concrete for your construction project, you will sometimes have to cut the slabs or stones to the desired dimensions. Only then can they be perfectly integrated into the design.
  
  

• Repair and maintenance:
  
  Damage or cracks in exposed aggregate concrete can occur over time. To repair these it may be necessary to cut out the damaged area and insert a new piece.

3. Tools and materials for cutting aggregate concrete

In order to successfully cut exposed aggregate concrete, you need the right tools and machines. Here are the main ones:

• Diamond cutting discs:
  
  Diamond cutting discs are special cutting discs that are coated with diamond particles. They are particularly good for cutting hard materials such as concrete.
  
  
  

  

• Cut-off grinder - for thick aggregate concrete
  
  A power cutter is an electric or gas powered tool used to cut concrete, stone, and other hard materials. Make sure that your cut-off grinder has enough power to cut particularly thick aggregate concrete elements.
  
  

• angle grinder
  
  An angle grinder can also be used to cut aggregate concrete as long as it is fitted with a suitable diamond blade. With the angle grinder you can achieve a cutting depth of up to 4.5 cm.
  
  

• Protective gear:
  
  Cutting aggregate concrete creates dust and chips that can pose a health hazard. Therefore, you should always wear safety goggles, hearing protection, gloves and a dust mask.

My experience: The separator is only required for particularly thick and/or many meters of cutting. Otherwise you can also use the angle grinder (flex).

4. Preparation for cutting aggregate concrete

Before you can start cutting aggregate concrete, some preparatory work is required:

• Planning and marking:
  
  Measure the area you want to cut and mark the cutting line with a pencil or chalk pen. Check the mark carefully to make sure it is clean and straight.
  
  

• Safety Precautions:
  
  Make sure your work area is well lit and has enough space to cut.

My experience: let your neighbors know that there may be some noise for a while. You should also follow the tips for dust-free cutting to keep dust pollution as low as possible.

5. Step-by-step instructions for cutting aggregate concrete

1. Sawing with the cut-off grinder:
   
   Make sure the concrete diamond blade is properly attached to the power cutter and that protective equipment is worn.
   
   Switch on the power cutter and increase the number of revolutions of the cutting disc to full speed.
   
   Guide the power cutter along the cutting line, making sure to work evenly and in a controlled manner. Carefully cut along the entire cutting line.

   

1. Post processing:
   
   After you've made the cut, smooth out any bumps or burrs with a diamond concrete cup wheel or diamond abrasive pad .
   
   Make sure to carefully finish the edges of the cut aggregate concrete for a clean and professional result.
   
   
   

6. Tips and tricks for optimal results

• For thicker aggregate slabs, use a guide bar to ensure a straight and precise cut.

• Cut the aggregate slowly and evenly to avoid cracking or damaging it.

• Make sure the power cutter or angle grinder and the diamond blade are sufficiently cooled throughout the cutting process to avoid overheating and premature wear.

My tip: Take regular breaks from cutting or cool the cutting disc by pouring some water on the cut .

7. Common mistakes and how to avoid them

• Cutting too fast: If you cut too fast, this can lead to cracks or fractures in the aggregate. Go slowly and carefully to avoid damaging the material. Don't apply too much pressure.

• Use of inappropriate tools: Always use the correct tools for the cutting process. Incorrect selection can lead to poor results and reduced tool life.

• Inadequate protective equipment: When cutting exposed aggregate concrete, the use of protective equipment is essential. Make sure you wear safety goggles, hearing protection, gloves and a dust mask to avoid injury or health problems.

8. Cutting alternatives to aggregate concrete

In some cases, cutting aggregate concrete may not be the best solution. Here are some alternatives:

• Break exposed concrete :
  
  If it is not important to get exact cut edges, you can break exposed concrete with a hammer and chisel. While this method is less precise, it can be sufficient in certain situations.

• Use of finished products:
  
  Instead of cutting aggregate concrete yourself, you can use prefabricated aggregate concrete slabs or blocks that already have the desired dimensions.

Care and maintenance of cut aggregate concrete

After cutting exposed aggregate concrete, it is important to properly care for and maintain the material to maximize its lifespan:

• Clean the aggregate regularly with water and a soft brush to remove dirt and deposits.
  
  
• Check the aggregate concrete for cracks or damage and repair them if necessary.
  
  
• Protect the aggregate from extreme weather conditions by covering it or treating it with a water-repellent seal.

9. Conclusion

Cutting aggregate concrete is an important and frequent application in many areas. Whether indoors or outdoors.

With the right preparation, the right tools and our step-by-step instructions, you should be able to cut exposed concrete precisely and safely.

Always stay safe and follow our tips and tricks for best results.

FAQ - Frequently asked questions about cutting aggregate concrete

1. Can I cut exposed concrete with a conventional handsaw?
   
   A conventional handsaw is not suitable for cutting exposed aggregate concrete because the material is too hard. Instead, use a power cutter or angle grinder with a diamond blade.
   
   

2. How deep should I cut in one go when cutting exposed aggregate concrete?
   
   It is advisable to carry out the cut in several passes, especially in the case of thick aggregate concrete slabs. Cut about a third of the way through the material first, then deepen the cut in subsequent passes until the desired depth is reached.

3. How long does it take to cut aggregate concrete?
   
   The duration of the cutting process depends on the thickness of the aggregate and the power of the cut-off machine. However, with proper handling and use of the appropriate tools, the cutting process should proceed quickly.

4. Can I use an angle grinder to cut aggregate concrete?
   
   An angle grinder can be used to cut aggregate concrete provided it is fitted with a suitable 125mm concrete diamond blade .

5. How do I dispose of exposed aggregate concrete after cutting?
   
   Washed concrete residues can be disposed of as building rubble. Make sure to comply with local regulations for the disposal of building materials and, if necessary, use the appropriate disposal sites or container services.