Evaluation of sand characterization (XRF/XRD/TGA) on the structural performance and thermal stability of deep beams

Deep beams are critical structural elements in reinforced concrete design, yet their complex stress distribution and strength behavior under varying loading conditions remain a challenge for engineers. This study investigates the influence of sand characterization on the mechanical and thermal performance of deep beams. Three sand samples (A, B, and C) were analyzed using sieve analysis, moisture content determination, compressive strength testing, X ray fluorescence (XRF), X ray diffraction (XRD), and Thermogravimetric analysis (TGA). Concrete specimens (I, J, and K) were prepared from each sand type and tested at 7, 14, 21 and 28 days of curing. Results revealed that Sand B, with the lowest silt fines content (4.95%) and highest fineness modulus (3.79), produced concrete Sample J with superior compressive strength of 20.29 N/mm^² at 28 days and characteristic strength of 16.98 N/mm^². XRF confirmed silica dominance with concentration of 66% to 74% in fine aggregates, while XRD highlighted Sand B’s high quartz content of 64 wt.%. TGA demonstrated enhanced thermal stability in Sample J, with reduced mass loss and improved fire resistance. These findings underscore the importance of aggregate characterization in optimizing deep beam performance, particularly under high temperature conditions, and provide insights for safer, more durable structural design.