Investigation of glass fiber reinforced concretes with different fiber length and weight fraction by fracture energy and non-destructive methods

Fracture energy test, non-destructive investigation, some of the physical and mechanical tests, and microstructural examinations were performed on GRC (glass fiber-reinforced concrete) with different fiber length and weight fractions. Alkaline-resistant glass (AR-GF) fibers with 6, 12, and 19 mm lengths were evaluated to produce GRCs. Weight fractions of 0.7 wt%, 1.3 wt%, and 2.0 wt% AR-GF fibers were used in the GRC mixtures. Fracture tests were performed on Single Edge Notched Beams (SENBs) to investigate fracture energy, crack resistance index (CRI), and flexibility index (FI) of GRCs. Dynamic modulus of elasticity and damping ratios of the GRCs were determined by performing resonant frequency tests on the SENB samples by ASTM C215 standard. In addition, compressive strength, static modulus of elasticity, electrical resistivity, ultrasonic pulse velocity (UPV), Schmidt hammer, and density tests were also performed on the cylindrical samples produced. Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR) analyses were performed to examine the microstructure of the GRC matrix in this study. Test results revealed that the mixtures containing 12 mm long fiber at 2.0 wt% dosage exhibited superior fracture energy by cracking resistance and flexibility index. Dynamic test results showed that the increase in fiber length and ratio increased the damping ratio of GRCs. In sum, with the study, it came out that fiber length had more significant relations with the experimental results once compared to the weight of fiber content.