Recycled glass could soon play a major role in greener construction, thanks to new research showing that it can help make building materials stronger and more sustainable.
Scientists from the University of Portsmouth and other institutions have found that powdered recycled glass, when mixed with lime and a small amount of cement, can be used to strengthen compressed earth blocks—an eco-friendly alternative to traditional bricks.
Compressed earth blocks, or CEBs, are made by mixing soil with water and compressing the mixture into block shapes under high pressure.
They are already seen as a more sustainable choice for building because they require less energy to produce than conventional bricks and concrete.
However, to make them stronger and more durable, stabilizing agents like cement are usually added—which can increase the environmental impact.
The research team wanted to explore whether recycled waste glass could replace some of the cement in these blocks.
They tested blocks that included different amounts of powdered recycled glass—ranging from 0% to 25%—and analyzed how strong and water-resistant the blocks became after 28 days. They also used powerful electron microscopes to examine the microstructure of the blocks and look for cracks or weaknesses.
Dr. Muhammad Ali, Associate Professor in Materials and Environmental Innovation at the University of Portsmouth, said the team was responding to growing demand for sustainable construction materials made from industrial waste. “We wanted to assess the properties of compressed earth blocks using recycled glass particles,” he said.
The results were promising. The strongest blocks were made with a mix of 10% recycled glass and 10% lime.
These blocks had a compressive strength of 5.77 megapascals (MPa)—a 90% improvement over unstabilized blocks, which reached only 3.03 MPa. In terms of tensile strength, the 10% recycled glass and lime blocks also performed best, showing a 30% improvement over blocks with no stabilizers.
Perhaps just as important, the blocks with 10% recycled glass showed no visible cracks after curing, while those with 25% recycled glass started to show micro-cracks. This suggests that 10% might be the ideal amount to balance strength and stability without causing damage to the material.
The researchers say their findings open the door for future studies into other important features, such as how these blocks perform in extreme temperatures or over long periods. With more research, recycled glass could become a staple ingredient in building materials, helping to reduce waste and make construction more sustainable—one block at a time.
Source: University of Portsmouth.
