In a groundbreaking study published in the ‘Journal of Sustainable Construction Materials and Technologies’, researchers from the Kwame Nkrumah University of Science and Technology have explored an innovative approach to asphalt production that could significantly reduce environmental impact while enhancing performance. The research, led by David A. Azong-bil from the Department of Civil Engineering, investigates the feasibility of replacing conventional granite aggregates with steel slag and palm kernel shell ash (PKSA), two waste materials that are often challenging to dispose of.
The construction sector has long grappled with the sustainability issues arising from the over-reliance on traditional rock aggregates. With large quantities of steel slag generated from steel production and PKSA as a byproduct of palm oil milling, the potential for repurposing these materials is not just a win for waste management but also a lucrative opportunity for the industry. “Our findings indicate that these waste materials can not only replace virgin aggregates but also enhance certain properties of asphalt mixtures,” Azong-bil stated.
The study conducted a comprehensive analysis of two sets of asphalt mixtures: a control mixture using crushed granite and hydrated lime, and a waste-based mixture incorporating steel slag as coarse aggregate and PKSA as fine aggregate and filler. Both mixtures utilized AC-30 viscosity-graded asphalt binder and were subjected to rigorous testing to evaluate their durability, fatigue cracking resistance, rutting resistance, and moisture damage susceptibility.
While the results showed that the waste-based mixture was slightly less durable than the control in terms of Cantabro abrasion loss, it excelled in cracking resistance, boasting a performance nearly double that of the granite-based mixture. “This indicates that while we may sacrifice some durability, we gain significantly in terms of resistance to cracking, which is crucial for the longevity of road surfaces,” Azong-bil explained.
Moreover, although the rapid rutting test suggested that the control mixture had a slight edge in rutting resistance, the overall performance metrics, including the Marshall quotient, indicated that the waste-based mixture held its ground. Both types demonstrated comparable moisture damage resistance, reinforcing the potential for steel slag and PKSA to serve as viable alternatives in asphalt production.
The implications of this research extend beyond environmental considerations. By integrating these industrial waste products into asphalt mixtures, the construction industry could see a reduction in material costs, particularly as the demand for sustainable practices continues to rise. The transition to using steel slag and PKSA could not only alleviate disposal issues but also pave the way for a more circular economy in construction materials.
As the construction sector increasingly prioritizes sustainability, studies like this one are crucial. They not only provide practical solutions but also challenge traditional practices, suggesting that the future of asphalt production may be more innovative and environmentally friendly than ever before. The research by Azong-bil and his team invites further exploration and field performance evaluations, potentially leading to broader adoption of these materials in the industry.
For more information on the work of David A. Azong-bil, visit the Department of Civil Engineering at Kwame Nkrumah University of Science and Technology.