Turning What was Once Waste Into Wealth is Becoming Mainstream.

In construction and demolition, where progress is often measured in mountains of rubble, a transformation is underway. The massive amounts of waste generated from demolition and excavation projects are no longer being dismissed as mere rubble. Recycling demolition waste into usable aggregate material is becoming mainstream and these discarded materials are seeing new life in the form of usable aggregate products, turning what was once ‘waste’ into a valuable resource. 

This innovative process not only offers significant financial benefits but also contributes to environmental sustainability. 

This article will delve into the process of recycling these materials, highlighting the environmental benefits and the potential for significant financial savings. 

The Evolution of Construction Waste

According to an article by (Miller 2021) published by the BBC,  The industry creating a third of the world’s waste – The construction industry is responsible for an estimated third of the world’s overall waste and at least 40% of the world’s carbon dioxide emissions.

Traditionally, demolition and excavation waste, which includes everything from concrete, bricks, and asphalt to metals, wood, and plastics, ended up in landfill sites. Today, however, we are witnessing an industry-wide shift towards sustainable practices, and recycling construction and demolition waste has become a top priority. 

Recycling Demolition Waste Into Usable Aggregate Products

Cobra 230 Impactor Crushing Asphalt

Demolition and excavation waste includes a wide range of materials such as concrete, bricks, wood, glass, metals, and plastic. Once considered waste, these materials can be recycled and reused in various construction projects, reducing the need for new raw materials and the environmental impact associated with their extraction and processing.

Recycling these materials promotes environmental sustainability and offers significant cost savings. By recycling, we can reduce the massive amounts of waste that end up in landfills and decrease the demand for new resources, leading to a more circular economy. 

Transforming Waste into Wealth

So, how do we transform piles of demolition and excavation waste into usable aggregate products? The process is multi-faceted and involves a series of steps: 

1. Waste Collection and Sorting: Waste is collected and sorted once the demolition and excavation process is complete. This sorting phase is crucial in separating recyclable materials from those that are not. 

2. Crushing and Screening:  Recyclable waste, which typically includes concrete, brick, and asphalt, undergoes crushing and screening processes. Here, large pieces of debris are broken down into smaller aggregate sizes suitable for construction use. This aggregate is then screened to ensure consistent size and quality. 

3. Quality Assurance:   Once the waste has been transformed into aggregate, rigorous testing is conducted to ensure it meets industry standards. This includes testing for aspects such as durability, hardness, and shape. 

4. Reuse and Recycling:   Once approved, the aggregate can be reused in various construction applications such as road base, fill material, and concrete production. 

The Environmental Benefits

The environmental benefits of recycling construction waste into usable aggregate are immense. Firstly, it dramatically reduces the volume of waste that ends up in our landfills, thus conserving valuable space. Secondly, it reduces the need for raw material extraction, thereby preserving natural resources and habitats. This also reduces transportation and production energy, minimizing our carbon footprint. 

The Financial Payoff

The financial advantages of recycling demolition and excavation waste are equally impressive. Businesses can significantly reduce their raw material and disposal costs by repurposing waste into usable aggregate products. In addition, a growing number of jurisdictions are implementing landfill taxes, providing further financial incentives to recycle. Also, with the rise of sustainable construction and green building certification programs, using recycled materials can enhance a project’s environmental credentials, making it more attractive to potential clients and investors. 

Natural Aggregates vs Recycled Aggregates

What are Natural Aggregates

Natural aggregates are available in different types depending on their uses. They consist of crushed or uncrushed materials like sand, gravel and rock from natural sources like riverbeds and glacial deposits. The material is often used to produce concrete, asphalt and base gravel for infrastructure like roads and buildings.

Using recycled aggregates has environmental benefits, including:

• Conserving natural resources by decreasing the demand for virgin materials
• Protecting local ecosystems and maintaining biodiversity level
• Reducing energy consumption, transport emissions and disposal of waste to landfill
• Reducing road haulage activities and decreasing road congestion, and increasing road safety

Using recycled aggregates has financial benefits, including:

• Producing recycled aggregate for resale is more cost-effective than sending unwanted materials to landfill and incurring landfill tax and transport costs.

Material Sources / End Products & Uses

C&D Waste

Material derived from the demolition of buildings (High % of concrete, brick, wood, plastics and metals)

Road, Sidewalk and Infrastructure Construction

Sidewalks, roads and other infrastructure are all made of concrete and asphalt, which can be crushed, screened and processed to make new concrete and asphalt mixes. Recycling asphalt also significantly saves asphalt oil when used in new mixes.

Vacuum Truck / Site Excavation

Material derived from excavating construction sites. (The gradation is variable and often contains a high percentage of silts & clays (63 microns)

Trommel Fines

Dry recycling residual fine materials. (Often containing high percentages of wood, plastics and organic matter)

Road Sweepings

Material derived from road sweepers/vacuum trucks often contains a high percentage of plastic and organic matter.

Contaminated Waste / Soil

They are categorized as Non- Inert due to the presence of heavy metals and hydrocarbons. (Eg. Material excavated after an oil spill or earthen material from chemical works)

Concrete Truck ‘Washout’

Concrete returned to the ready mix depot, which was surplus to requirements on site.

What Recycled Materials Are Used For:

Sized Aggregates

• They are used as Base Material for roads, pathways and drainage.
• Top Soil recycled from construction sites, this clean inert multi-sourced topsoil is suitable for landscaping on commercial or industrial building sites.

Metals

• They are used for new ferrous and non-ferrous metal products.

Recycled Washed Aggregates

• They are used for concrete and asphalt products, drainage, landscape stone, and pipe bedding.

Recycled Washed Sands

• They are used for concrete products, pipe and cable bedding and landscape brick bedding.
• Reject sand can be sold as fill material or blended into soils and compost for landscaping projects.

In conclusion, recycling demolition and excavation waste into usable aggregate products is not just an eco-friendly move—it’s a wise business decision. By turning waste into wealth, we can build a sustainable future for the construction industry while simultaneously reaping significant financial benefits. With every piece of rubble we recycle, we’re laying the foundation for a greener, more prosperous future. As the saying goes, “One man’s trash is another man’s treasure.” In the world of construction, this couldn’t be more true.