Recycled concrete has been revolutionary for its numerous benefits and the limited usage of natural resources. It promotes sustainability and stands as a replacement for virgin concrete. Here is a detailed overview of recycled concrete, its benefits, applications, and how it compares with virgin concrete.
What is Recycled Concrete?
Recycled concrete is produced by grinding and crushing preexisting concrete from demolished concrete structures. This recycled concrete can be reused for construction projects instead of being disposed of as non-biodegradable concrete in landfills. It is a sustainable and economical alternative to fresh cement and is used for numerous purposes.
Applications of Recycled Concrete
Roads and Pavements
Recycled concrete aggregate is strong and durable enough to withstand heavy loads, making it suitable for road construction. It is used as a base material for roads, parking lots, and driveways as well as a subbase material for asphalt pavements. It can also be used to construct road shoulders, patios, and walkways.
Drainage & Retaining Wall
This concrete has a porous structure and is most commonly used to construct drainage trenches, drains, and stormwater management systems. It can also be used to build retaining walls to control the water flow.
Backfill
Another popular application of recycled concrete is as a backfilling material in construction sites and for levelling the ground. It can be used to fill trenches and foundations and construct embankments for roads, railways, and infrastructure projects.
Precast Materials
Recycled concrete is used to make Precast bricks, blocks, tiles, paving stones, and other precast materials for construction projects. This material helps construct sustainable green buildings, reducing their environmental impacts.
Benefits of Recycled Concrete
- It limits the usage of natural resources and lowers the environmental impacts caused by mining and reducing carbon footprint.
- It consumes less energy compared to the manufacturing of virgin aggregates, making it one of the sustainable options.
- It reduces the amount of concrete waste that is usually dumped as non-degradable concrete into landfills.
- When recycled properly and mixed with other materials, recycled concrete can achieve equal or greater strength and durability than virgin concrete.
- It reduces the overall cost of concrete compared to virgin concrete materials, saving money for large-scale projects.
- Recycled concrete can be easily available locally at demolition sites, which cuts the cost of transportation.
Process of Concrete Cycling
Collecting
Collect the concrete from the demolition site, such as buildings, pavements, and foundations. Transport the collected materials to the recycling plant for crushing and grinding. The demolition structures can be easily available in the locality, and the recycling crusher may be set up on-site to reduce transportation costs and save time.
Crushing
The large pieces of concrete collected are crushed and ground in large equipment with jaws and impactors. This reduces the size of the concrete and achieves the desired aggregate size suitable for different construction applications.
Removing Contaminants
After crushing and grounding, the concrete material is cleaned to remove contaminants such as dirt, wood, and debris. Additionally, steel reinforcements are removed, and the concrete is sorted based on size, from fine particles to large chunks.
Quality Testing
Quality control tests are conducted on recycled concrete to determine whether it meets industry standards. The tests calculate the concrete’s strength, cleanliness, and usability in different construction applications.
Mixing with Raw Materials
If recycled concrete doesn’t meet industry standards, virgin aggregates such as cement and water may be added to achieve the consistency and characteristics of concrete suitable for construction.
What is Recycled Concrete Aggregate?
Recycled Concrete Aggregate is an aggregate obtained by processing and recycling preexisting concrete structures. It replaces virgin coarse and fine aggregates such as gravel, sand, and other natural resources in construction. These recycled materials are used as a base subbase in road construction and other building masonry projects.
Recycled Concrete vs Virgin Aggregate Concrete
| Recycled Concrete | Virgin Aggregate Concrete |
| The recycled concrete is made of crushed concrete containing original aggregates and hydrated cement paste. | Virgin concrete includes sand, gravel, rock and mined earthy materials. |
| Due to its higher water absorption rate, recycled concrete is limited in workability and unsuitable for exposed and load-bearing structures. | The workability of virgin aggregates is higher and can be used in almost all construction processes. |
| The risk of concrete segregation is higher due to the well-rounded shape of the recycled aggregate. | The segregation risk is lower in comparison due to its angular aggregate shape. |
| The compression strength of recycled concrete depends on the aggregate quality and efficiency of the recycling process. | The compression strength of virgin concrete is slightly higher in comparison. |
| The permeability of the virgin concrete is higher. | The permeability of virgin aggregates is lower in comparison. |
| It has a slightly low resistance to elastic deformation compared to virgin concrete | It has medium resistance to elastic deformation and can withstand stress to a moderate level. |
| The density of recycled concrete is 15% less in comparison. | The density of virgin concrete is slightly denser than recycled concrete. |
Conclusion
As the world is targeting green technology and sustainable construction, using recycled concrete becomes crucial. It provides numerous benefits both environmentally and economically. It is a true revolution in the construction field and leads to sustainable construction, limiting the usage of natural resources and energy consumption. Although it is not as strong and workable as virgin concrete, the efficient recycling process and advanced technologies could help achieve industrial standards. It would be no wonder if recycled concrete completely replaces virgin concrete.
FAQs
Yes, recycled concrete is widely used as backfilling material in trenches and foundations of buildings. It is also used as base and subbase material in constructing roads, railways, and walkways.
Recycled concrete absorbs more water, reducing the structure’s strength and durability. Poorly recycled concrete has a high risk of segregation, which could affect the overall structural integrity.