In the quest for sustainable construction materials, researchers have turned to recycled aggregate concrete (RAC) as a promising alternative to traditional concrete. A recent study led by Jian-Hua Jiang from the College of Civil and Transportation Engineering at Hohai University has shed new light on enhancing the performance of RAC, with significant implications for the construction and energy sectors.
The study, published in the International Journal of Concrete Structures and Materials (한국콘크리트학회지), focuses on the dynamic compressive performance of recycled concrete, considering the effects of pretreatment of recycled coarse aggregates (RCAs) and calcium leaching. The research team found that treating RCAs with a 5% water glass solution significantly improved the material’s properties.
“By soaking RCAs in a water glass solution, we observed a notable reduction in water absorption, crushing index, and porosity,” explained Jiang. After just 12 hours of soaking, the water absorption of RCA decreased by 13.7%, while the crushing index and porosity dropped by 11.3% and 11.2%, respectively. This pretreatment process enhances the quality of RCAs, making them more suitable for use in concrete.
The dynamic compressive performance tests, conducted using the split Hopkinson pressure bar device, revealed that the dynamic compressive strength and dynamic increase factor (DIF) of pretreated recycled coarse aggregate concrete (PRCAC) are highly sensitive to strain rate. As the strain rate increased, so did the dynamic compressive strength. Moreover, the dynamic compressive strength of PRCAC exhibited a positive correlation with the incorporation ratio of pretreated RCAs (PRCAs) and a negative correlation with the duration of calcium leaching.
The research also highlighted the impact of calcium leaching on the performance of PRCAC. As the duration of calcium leaching increased, the sensitivity of PRCAC to strain rate also increased, while the degree of strength degradation due to calcium leaching decreased with longer soaking durations of RCAs.
The findings of this study contribute to the improvement of recycled concrete performance and the accurate evaluation of its dynamic mechanical properties. For the construction industry, this means a more reliable and sustainable material that can withstand high-impact loads, such as those experienced in earthquake-prone regions or high-traffic infrastructure projects.
In the energy sector, the enhanced performance of recycled concrete could lead to more durable and efficient energy infrastructure. For instance, the use of PRCAC in the construction of wind turbine foundations or solar panel installations could extend the lifespan of these structures, reducing maintenance costs and improving overall energy output.
As the world continues to grapple with the challenges of climate change and resource depletion, the development of sustainable construction materials like PRCAC is more critical than ever. This research not only advances our understanding of recycled concrete but also paves the way for innovative applications in the construction and energy sectors.
“Our findings open up new possibilities for the use of recycled materials in high-performance concrete applications,” said Jiang. “This is a significant step towards a more sustainable and efficient construction industry.”