In the world of construction, deep beams are the unsung heroes, quietly supporting structures where space is at a premium. These structural members, characterized by their large depth-to-span ratio, are primarily designed to withstand shear forces rather than bending. Now, a groundbreaking study led by Mosa Jumaa Mosa from Mustansiriyah University in Iraq is challenging conventional wisdom about the composition of concrete used in these critical structures.
Mosa and his team have been investigating the shear behavior of reinforced concrete deep beams cast using concrete with a single size of coarse aggregate. This is a departure from the norm, as most design references recommend graded aggregates to prevent segregation and ensure uniform strength. “We wanted to explore the feasibility and implications of using single-size coarse aggregate in deep beam construction,” Mosa explains. “The results were quite revealing.”
The study involved casting and testing 15 reinforced concrete deep beams under two-point loading. The specimens were divided into three groups based on the coarse aggregate size and shear span-to-effective depth ratio (a/d). The experimental results showed that beams with 20 mm and 25 mm coarse aggregates outperformed those with 15 mm and 37.5 mm aggregates. “The shear strength of deep beams is influenced by the size of coarse aggregate and the a/d ratio,” Mosa notes. “Both factors interact to affect the overall shear behavior.”
So, what does this mean for the construction industry, particularly the energy sector where deep beams are often used in power plants and other large structures? The findings suggest that using single-size coarse aggregate could potentially simplify the concrete mixing process, reduce material costs, and even enhance the structural performance of deep beams. “This could lead to more efficient and cost-effective designs in the future,” Mosa speculates.
The research, published in the journal ‘Heritage and Sustainable Development’ (translated to English as ‘التراث والتنمية المستدامة’), opens up new avenues for exploration in the field of concrete technology. As the construction industry continues to evolve, understanding the nuances of material composition and its impact on structural behavior will be crucial. Mosa’s work is a significant step in that direction, offering a fresh perspective on an age-old material.