Facts about Recycling of Concrete

What is recycling of Concrete ?

Recycled concrete is the concrete produced from the method of reusing the concrete, obtained from the demolition and renovation of the old buildings and infrastructure. It is gaining a lot of popularity due to its efficiency and effectiveness. Apart from this, it has a lot of other benefits which has made it a very attractive option for environment friendly building construction.

Recycling of waste concrete is done to reuse the concrete rubble as aggregates in concrete. The recycled aggregates have less crushing strength, impact resistance, specific gravity and has more absorption value as compared to fresh aggregates.

Millions of tonnes of waste concrete is generated every year around the world due to following reasons:

Demolition of old structure,

Destruction of buildings and structures during earthquakes and wars,

Removal of useless concrete from structures, buildings, road pavements etc.

Waste concrete generated due to concrete cube and cylinder testing, destructive methods of testing of existing structures etc.

Methods of Recycling Concrete

The equipment used for crushing the concrete rubble generally consists of a rubble crusher, side discharge conveyor, screening plant and a return conveyor from the screen to the crusher inlet. The return conveyor sends back the oversized materials or the other under crushed materials which needs reprocessing. The rubble must be free of all the unwanted materials such as plastic, wood, paper and other trash materials. Metals are permissible, since they can be removed by magnets or other sorting devices. These metals later can be recycled by meting it down and used for other purposes. The other aggregates present in the demolition waste can further be recycled by subjecting it to crushing. The crushing is achieved by using the crusher equipment.

Once the crushing is done, the finely crushed cement can be used for construction purposes whereas the other materials are sorted out through various methods such as hand picking or water floatation. They can either be used as they are or can be subjected to reprocessing. By carrying out the crushing process on the construction site, the transportation cost can be reduced greatly.

Circular Production Chain for concrete

Until recently, a circular production chain was not possible for concrete. Concrete could not be reused to produce new concrete, at least not in an environment friendly manner. Traditionally, large pieces of concrete is reduced to smaller pieces called rubble granules. These rubble granules are mainly used as a foundation material for roads. Smart crusher has developed a technique for recovering the sand, gravel and the cement from concrete. This unique technique has been tested and proven on a laboratory scale and in practice.

Traditional concrete crushers are huge. A traditional concrete crusher breaks right through the sand and gravel. Smart crusher on the other hand, crushes only the cement stone leaving the sand and gravel undamaged. The smart crusher not only makes the concrete chain circular, it also makes the sand and gravel better than new. The most important aspect however, is that all the cement can be retrieved clean and unpolluted by fine broken sand. This is a very positive development in the construction field since it uses lesser electric power and economical at the same time.

Uses of Recycled concrete

Finer pieces of recycled concrete can be used as gravel for new construction projects. Sub-base gravel is laid down as the lowest layer in the road with fresh concrete or asphalt poured over it.

Recycled concrete can be used as an efficient building material, if it is crushed properly and kept free of unwanted materials and contaminants.

A process called Rubberization can be achieved through recycled concrete. In this process, the pavement concrete can be broken down in its own place and used as a base layer for the new pavement.

Larger pieces of crushed recycled concrete can be used for Riprap revetments, which are a very effective and popular method of controlling erosion.

It is very simple to make new cement from cement stone obtained from the crushers.

Wired cages can be filled with crushed concrete and stacked together to provide economical retaining walls.

Benefits of Reused concrete

Firstly, the waste produced during construction can be reduced immensely by controlling the wastage of raw materials used in the manufacturing process of concrete. The CO2 emission can be controlled to a great extent by using the smart crushers to crush the recycled concrete. The recovered concrete is economic and environment friendly. The transportation cost can also be reduced by carrying out the recycling process in the same site where the demolition took place.