The effect of variable fiber parameters on workability and fracture energy of self-compacting concretes containing basalt and glass fiber

The aim of this study is to determine the effects of fiber length and fiber content on the fresh concrete properties of self-compacting concrete containing basalt and glass fiber and to develop recommendations for various construction types by determining optimum fiber length and amount. In the experimental studies, flowability, filling ability, viscosity and passing ability of self-compacting concrete mixtures were determined in fresh state. Compressive strength, flexural strength, splitting tensile strength, sorptivity coefficient and abrasion resistance of the samples cured for 28 days were determined. In addition, the change in ductility of self-compacting concretes was determined by using fracture energies obtained from notched beam specimens. As a result, the change in fiber amount and fiber length adversely affected fresh concrete properties. Also basalt fiber reduced fresh concrete properties more than glass fiber. The flexural strength, tensile strength and abrasion resistance of hardened concrete specimens increased with increasing fiber length and fiber content. Also, sorptivity increased and the compressive strength generally decreased depending on the fiber size and fiber amounts in both types of fibers. Compared with the reference mixture, the fiber-containing self-compacting concretes showed an increase of 10% to 55% in the fracture energy values.