A team of researchers from the University of Portsmouth has developed an innovative method to incorporate recycled glass into construction materials, specifically compressed earth blocks (CEB). This approach could significantly enhance the sustainability of building materials and reduce the environmental impact associated with traditional glass recycling processes.
The research team, which included scientists from three other universities, focused on utilizing powdered discarded glass as a stabilizing agent in CEBs. These blocks are made from a mixture of soil, water, and typically cement. By compressing these materials under high pressure, they create durable building blocks that emit far fewer carbon emissions compared to conventional fired bricks.
The standard CEB formulation relies on cement as a binder to improve the structural integrity of the blocks and protect against water damage. However, the team aimed to replace cement with alternatives that would provide similar strength and durability. According to Dr. Muhammad Ali, who co-authored a paper published in Discover Civil Engineering in March 2024, extensive testing led to an optimal mix of materials.
Dr. Ali noted, “At each percentage level we tested for water absorption, how resistant to breaking the blocks were when compressed, and to determine the maximum stress the block could withstand while being stretched or pulled, before breaking or becoming deformed.” The results indicated that a composition of 10% lime and 10% recycled glass particles produced the strongest blocks, showing no cracking under significant pressure.
The researchers recommend that CEB manufacturers consider this mix to create more sustainable building materials. While initial findings are promising, they acknowledge that further studies are necessary to assess the long-term durability of these blocks under various environmental conditions.
This innovation comes at a time when the need for sustainable construction practices is growing, particularly in developing countries. CEBs are well-suited for low-rise residential and community buildings, such as schools and clinics, especially in climates with low to moderate humidity. They are not ideal for high-rise buildings typical of urban environments in developed nations. However, the local sourcing of materials and labor-intensive production make recycled glass-infused CEBs an attractive option for sustainable construction in many regions.
Globally, scientists are actively seeking ways to divert glass from landfills. Beyond CEBs, recycled glass can be utilized in various applications, such as fire-resistant cladding, as a sand substitute in concrete for 3D printing, and even in innovative bricks that offer better insulation than conventional options. Some research has even focused on developing a type of glass that can decompose when composted, showcasing the versatility of this material.
As the construction industry looks for ways to minimize its environmental footprint, the integration of recycled materials like glass into building products could play a critical role in shaping a more sustainable future. While the demand for CEBs needs to grow to make a significant impact, this research highlights a promising pathway for reusing waste glass and reducing the energy and resources typically required for traditional recycling methods.