Recycling Concrete: Extending the Lifespan of High Emission Materials

When discussing sustainability in architecture, wooden materials and greenery are often the main topics. To achieve net zero, architects also try to use recycled materials, which are commonly either wood, steel, or plastic. Other than that, there are things one should also consider: the treatment of concrete as one of the most used construction materials that has no truly equivalent substitute yet.

Casa Alferez by Ludwig Godefroy Architecture (cr: Rory Gardiner)

Concrete continues to be researched and developed so that materials that produce high emissions can be more “environmentally friendly.” This effort is necessary considering that concrete is in high demand in the architectural industry, and many building demolitions are needed to construct other new buildings. The demolition work results in heavy waste, including concrete. Then, can concrete be recycled?

PLOT #4371 by Bernard Khoury (cr: DW5)

Yes, concrete can be recycled using the heavy-duty machines developed today. In short, concrete fragments are broken down, additives are inserted into them, one substance is separated from another, and finally, a carbonated powder and cleaned aggregate are produced. The final result becomes a mixture to make new concrete.

Habitat 67 by Moshe Safdie (cr: Gili Merin)

Recycling certainly impacts the environment. First, there are fewer landfills, as heavy construction materials are not thrown away as waste. Second, the practice reduces the mining of the virgin materials that make up concrete, such as gravel. According to BBC Science Focus, one ton of recycled concrete saves 6,182 liters of water and 900 kg of CO2.

Princesa Building by Fernando Higueras (cr: Roberto Conte)

Currently, only a few architects or building owners use recycled materials for various reasons, such as the porosity level, decreased performance, and uneven quality. However, in addition to structural functions, recycled concrete can be used as gravel replacement, road base materials, landscape elements, stream beds for erosion control, and pipe bedding. On the one hand, the development of technology has positive impacts on the environment, especially in the architecture industry, which is destructive in nature. On the other hand, recycled products have yet to reach their optimal levels, and it is a reminder for architectural practitioners to always build wisely.