How is Concrete Recycled?
Do you want to know how concrete is recycled? Here is the step-by-step process on how companies recycle concrete.
1. Collecting Concrete
Collection of concrete involves identifying construction sites where broken concrete is available and coordinating with the site owner or contractor to arrange for its collection. This may involve obtaining necessary permits and coordinating with local debris management authorities to ensure proper disposal of any used materials removed during the process. Once collected, the concrete is transported to a recycling center where it can be sorted, crushed, and processed into a new material for reuse in construction projects.
Crushing the concrete is an essential step in the process of recycling it into a new material that can be used for construction. The process involves using a crushing machine such as a jaw crusher, impact crusher, or cone crusher to break down the concrete into smaller pieces. The size of the crushed concrete pieces will depend on the desired end-use of the recycled material.
3. Secondary Crushing and Screening
After the initial crushing process, the recycled concrete undergo secondary crushing and screening to further refine the material for its intended use. Secondary crushing involves using a smaller crushing machine to break the larger pieces of concrete into even smaller pieces. This process is particularly useful for producing smaller-sized aggregate for use in concrete mixes as well as to identify and remove any dirt that may compromise the quality of the concrete.
There are different types of equipment that can be used for secondary crushing and screening of concrete. These include the following.
- Impact Crushers – These crushers use impact force to break down the concrete into smaller pieces. They are generally used for larger pieces of concrete and are efficient at producing consistent, high-quality aggregates.
- Cone Crushers – These crushers use compression force to break down the concrete into smaller pieces. They are generally used for smaller pieces of concrete and are effective at producing fine, uniform aggregates.
- Vibrating Screens – These screens are used to separate the crushed concrete into different sizes based on the desired end-use. They can be used in conjunction with crushers to produce a more uniform product.
- Trommel Screens – These screens use a rotating drum to separate the crushed concrete into different sizes. They are particularly useful for separating fine particles from larger pieces of concrete.
- Jaw Crushers – These crushers are commonly used for primary crushing but can also be used for secondary crushing of smaller pieces of concrete.
4. Separating Small and Large Aggregates
Separating small and large aggregates is an important step in concrete recycling, as it ensures that the resulting recycled concrete has a consistent size and quality. This separation can be accomplished through a variety of methods, including:
- Screening – The recycled concrete can be passed through a series of screens of varying sizes to separate out small and large aggregates. This method is effective at producing a uniform product and can be used for a variety of end-uses.
- Air classification – This method involves using air to separate the small and large aggregates based on their size and weight. The larger, heavier aggregates will fall to the bottom while the smaller, lighter aggregates will be carried away by the air.
- Magnetic separation – This method is used to separate out any metal contaminants that are present in the recycled concrete. A magnetic separator is used to attract and remove metal particles, leaving behind the small and large aggregates.
5. Washing to Produce Clean Aggregates
Washing is another important step in the process of producing clean aggregates during concrete recycling. The process involves using water to remove any remaining contaminants from the recycled concrete, such as dirt, clay, or other debris.
The washing process typically involves placing the recycled concrete in a washing machine, which uses water and sometimes a mild detergent to clean the material. The machine agitates the concrete to remove any remaining contaminants, and the resulting wash water is collected and treated before being discharged to ensure that it meets local environmental regulations.