In the heart of Sri Lanka, researchers are turning industrial waste into a building block for a more sustainable future. A groundbreaking study led by BHJ Pushpakumara from the Department of Civil Engineering at the General Sir John Kotelawala Defence University has revealed that copper slag waste (CSW), a byproduct of ship corrosion removal, can significantly enhance the performance of masonry blocks when used as a fine aggregate replacement.
The research, published in *Results in Engineering* (translated from the original Sinhalese title), demonstrates that replacing natural sand with CSW in cement masonry blocks can lead to substantial improvements in mechanical properties and energy efficiency. “We found that blocks with 100% CSW exhibited a 60% increase in compressive strength and a 42% improvement in flexural strength,” Pushpakumara explained. “Moreover, the thermal conductivity was reduced by 46%, which is a significant step towards more energy-efficient buildings.”
The study analyzed blocks with varying levels of CSW replacement (0%, 25%, 50%, 75%, and 100%) and conducted tests for compressive strength, flexural strength, thermal conductivity, and density. The results showed that higher CSW content consistently improved block performance. The enhanced properties can be attributed to the rough surface of CSW particles, which improves interlocking and bonding, and the high content of SiO2, Fe2O3, and CaO in CSW, which promotes pozzolanic reactions.
From a commercial perspective, the findings are particularly relevant to the energy sector. Buildings account for a significant portion of global energy consumption, largely due to heating and cooling demands. By incorporating CSW into masonry blocks, the construction industry can contribute to reducing energy consumption and CO2 emissions. “A 100% replacement level results in cradle-to-gate reductions of approximately 6% in CO2 emissions,” Pushpakumara noted. “This is a significant step towards more sustainable and environmentally responsible construction practices.”
The study also highlights the economic benefits of using CSW. The cost of cement blocks can be reduced by up to 36% when using 100% CSW replacement. This cost savings, combined with the environmental benefits, makes a compelling case for the widespread adoption of CSW in construction.
The research not only offers a sustainable alternative to conventional materials but also promotes the recycling of industrial waste. By reducing reliance on natural sand, the construction industry can minimize its environmental impact and contribute to a more circular economy.
As the world grapples with the challenges of climate change and resource depletion, innovative solutions like this one are crucial. The findings of this study have the potential to shape future developments in the field of sustainable construction, paving the way for a more energy-efficient and environmentally responsible built environment. “This research opens up new possibilities for the use of industrial waste in construction,” Pushpakumara concluded. “It’s an exciting time for sustainable innovation in our industry.”