In the heart of the construction industry, a groundbreaking study led by Johnson Ngugi from the Department of Mechanical and Manufacturing Engineering has unveiled a promising solution to two pressing environmental issues: quarry waste and plastic pollution. The research, published in ‘The Scientific World Journal’ (translated to ‘The Scientific World Journal’), explores the feasibility of transforming basaltic quarry waste (BQW) and recycled high-density polyethylene (HDPE) into sustainable construction materials.
Imagine the vast amounts of fine rock aggregate produced as a by-product of the rock-crushing process in quarries. This material, known as quarry waste, is not only environmentally hazardous when poorly disposed of but also represents a significant waste of resources. Similarly, the accumulation of plastic waste, particularly HDPE, poses a severe threat to ecosystems worldwide. Ngugi’s research offers a compelling solution to both problems by recycling these materials into useful construction products.
The study involved melt-mixing recycled HDPE and BQW in a single-screw extruder, followed by transfer-moulding into experimental samples. The results were intriguing. “No significant chemical transformations were detected by Fourier transform infrared spectroscopy,” Ngugi explains, indicating that the process did not alter the fundamental properties of the materials. This stability is crucial for ensuring the reliability and longevity of the resulting construction materials.
Thermogravimetric analyses revealed an improvement in the thermal stability of HDPE with the addition of BQW. This enhancement is particularly significant for the energy sector, where materials must withstand high temperatures and harsh conditions. “The increase in thermal stability suggests that these materials could be used in applications where heat resistance is crucial,” Ngugi notes.
Scanning electron microscopy imaging showed generally poor adhesion between the two phases, which could be a challenge for future development. However, the study found that both tensile and impact strength initially increased but decreased at higher filler loading. This finding suggests that there is an optimal balance between BQW and HDPE that maximizes strength properties.
The research also highlighted improvements in stiffness, compressive strength, compressive modulus, density, and hardness with increasing filler content for all particle sizes. These enhancements make the material suitable for various construction applications, including roofing tiles and paving blocks. The increase in water absorption with increasing filler content was not significant, ensuring that the material remains durable in various weather conditions.
The implications of this research are far-reaching. By transforming quarry waste and recycled HDPE into construction materials, the industry can significantly reduce its environmental footprint. This innovation could lead to the development of new, eco-friendly construction products that meet the demands of the energy sector and beyond. As the construction industry continues to evolve, the integration of sustainable materials like those developed by Ngugi and his team will be crucial in shaping a greener future.
The study’s findings open the door to numerous possibilities. Future research could focus on optimizing the adhesion between BQW and HDPE to further enhance the material’s strength properties. Additionally, exploring the use of these materials in other construction applications, such as insulation or structural components, could yield even more benefits.
The construction industry is on the cusp of a sustainable revolution, and Ngugi’s research is a significant step forward. By turning waste into valuable resources, we can build a more sustainable future for all.