Fracture behavior and mechanical properties of concrete with artificial lightweight aggregate and steel fiber

• Fly ash lightweight aggregate (LWA) were produced by using cold bonding process.
• LWA was used as coarse aggregate at two volume fraction in the concrete production.
• Effect of steel fiber aspect ratio and volume fraction on fracture properties were investigated.
• Fracture properties of the concrete were remarkably affected by using LWA and steel fiber.

In this study, the mechanical and fracture properties of steel fiber (SF) reinforced cold bonded fly ash lightweight aggregate concretes (LWACs) were experimentally investigated. The LWACs were produced with constant water-to-cement ratio of 0.40 and two different volume fractions of lightweight coarse aggregates (LWCA). Three types of hooked-end SFs with aspect ratios of 55, 65, and 80 were utilized 0.35%, 0.70%, 1.00%, and 1.50% of concrete volume. Effectiveness of aspect ratio, SF volume fraction, and LWCA content on the compressive, splitting, and flexural strengths as well as the modulus of elasticity, fracture energy and characteristic length of the concrete were investigated at the end of 28-days of water curing. Test results revealed that the utilization of SF crucially enhanced the splitting tensile and flexural strengths, fracture energy and characteristic length. The compressive strength, however, were not affected considerably by SF addition. Moreover, the concrete properties mentioned above were significantly influenced by artificial fly ash LWCA content.