Evaluating the flexural behavior of green copper slag-contained steel fiber reinforced SCC beams with/without initial notches

Abstract

Nature-friendly concrete composites containing hooked-end steel fibers (SF) and copper slag (CS) aggregates can play important roles in sustainable construction, preventing the nature destruction, reducing brittle fracture and improving formability of concrete elements. To this end, effects of SF (0.1, 0.3, and 0.5%) and CS (20, 30, 40, 50 and 60%) on the compressive strength and microstructure of concrete composites were examined and the flexural behavior and toughness of beams with/without notches were evaluated and compared with the control design (no SF/CS) using Post Crack Strength (PCS), CECS 13, ASTM C1018, JSCE-SF4, ASTM C1609 and JG/T 472 models. Same laboratory setup and specimen dimension were used for accurate evaluations and results showed that CS aggregates improved the properties of fresh concrete and its workability was reduced by high SF volumes. Increasing the latter from 0.1 to 0.5% increased the optimal CS from 20 to 50% to achieve better compressive strength, and increasing the CS volume up to 30% strengthened the microstructure of SF-reinforced composites. Compared with notched (N) specimens, unnotched (UN) ones had higher peak loads and lower flexural strengths. At the lowest fiber volume, CS effects on both flexural behavior and fracture toughness were greater, and JG/T 472 method calculated the flexural toughness better than the other mentioned methods because of separating the pre- and post-peak load areas in the load–displacement curve and also using the flexural strength (which is affected by peak load).